Average Bulk Density Research Articles

Mutual events in the Cold Classical transneptunian binary system Sila and Nunam

Hubble Space Telescope observations between 2001 and 2010 resolved the binary components of the Cold Classical transneptunian object (79360) Sila–Nunam (provisionally designated 1997 CS29). From these observations we have determined the circular, retrograde mutual orbit of Nunam relative to Sila with a period of 12.50995±0.00036days and a semimajor axis of 2777±19km. A multi-year season of mutual events, in which the two near-equal brightness bodies alternate in passing in front of one another as seen from Earth, is in progress right now, and on 2011 February 1UT, one such event was observed from two different telescopes. The mutual event season offers a rich opportunity to learn much more about this barely-resolvable binary system, potentially including component sizes, colors, shapes, and albedo patterns. The low eccentricity of the orbit and a photometric lightcurve that appears to coincide with the orbital period are consistent with a system that is tidally locked and synchronized, like the Pluto–Charon system. The orbital period and semimajor axis imply a system mass of (10.84±0.22)×1018kg, which can be combined with a size estimate based on Spitzer and Herschel thermal infrared observations to infer an average bulk density of 0.72-0.23+0.37gcm-3, comparable to the very low bulk densities estimated for small transneptunian binaries of other dynamical classes.

Suitability of the Physical Properties of Soil for Crop Production: A Study in Tangail Sadar

Use of imbalanced chemical fertilizer and changing crop and cropping pattern are becoming a serious threat for the sound environment of the soil. The study provided an assessment of the present status of soil quality of Tangail Sadar based on the laboratory analysis of physical parameters such as bulk density, water holding capacity, sand, silt and clay percentage from July, 2010 to December, 2010. 40 soil samples from 20 different places were collected from 0-15 cm and 15-30 cm depth of the soil from 5 locations mentioned as Porabari, Santosh, Gharinda, By-pass and Ashekpur. The study conducted revealed that among the 40 soil samples, 30 soil's textural classes are sandy clay loam, 7 are sandy clay and rests 3 are clay loam and the pH value ranges from 5.3 to 6.4. The comparative analysis shows that the average texture class is sandy clay loam, which is not relevant to the standard level because the standard texture class is loamy. The average moisture percentage, bulk density and water holding capacity are found 2.865 %, 0.0926 gm/cm3 and 9.44% respectively which are almost similar to standard values and almost soil are suitable for plant growth.DOI: http://dx.doi.org/10.3329/jesnr.v4i2.10160 J. Environ. Sci. & Natural Resources, 4(2): 121-125, 2011

AVAILABILITY AND PHYSICAL PROPERTIES OF RESIDUES FROM MAJOR AGRICULTURAL CROPS FOR ENERGY CONVERSION THROUGH THERMOCHEMICAL PROCESSES

Plant residues from the major agricultural crops (w heat, rice, corn, soybean, sugarcane, coffee and co tton) are abundantly available renewable resources that can b e used to supply energy through thermochemical conversion processes. The available amounts of plant residues from these crops and their physical properties (moi sture content, particle size, bulk density and porosity) wer e determined. The annual residues from the wheat, r ice, corn, soybean, sugarcane, coffee and cotton were 763.42, 698.10, 1729.92, 416.62, 16.85, 4.01 and 107.13 million tons, respectively. The total amount of plant residues wa s estimated at 3736.05 million tons with total ener gy content of 66.92 EJ. These residues can replace 2283.52 millio n tons of coal, 1551.78 million tons of oil and 184 7.63 million m 3 of natural gas. The moisture contents were 7.79, 6 .58, 6.40, 7.30, 8.15, 7.86 and 7.45% for the wheat straw, rice straw, corn stalk, soybean stalk, sugar cane stalk, coffee husk and cotton stalk, respectiv ely. The corn stalk and sugarcane stalk had a convex particle siz e distribution, the soybean stalk and cotton stalk had a concave particle size distribution, the wheat straw and ric e straw had an increasing trend particle size distr ibution and the coffee husk had a decreasing trend particle size di stribution. The average particle sizes for the whea t straw, rice straw, corn stalk, soybean stalk, sugarcane stalk, coffee husk and cotton stalk were 0.42, 0.40, 0.49, 0.43, 0.55, 0.67 and 0.38 mm, respectively. The average bulk density was 160.75, 166.29, 127.32, 242.34, 110.86, 3 49.06 and 230.55 kg m -3 for the wheat straw, rice straw, corn stalk, soybe an stalk, sugarcane stalk, coffee husk and cotton stalk, respectively. The average porosity was 5 1.25, 83.20, 58.51, 68.03, 77.58, 64.85 and 74.55% for the wheat straw, rice straw, corn stalk, soybean stalk, sugarcane stalk, coffee husk and cotton stalk, res pectively. The results obtained from this study indicate that diff erent plant residues have different physical proper ties.

PHYSICAL PROPERTIES OF CORN RESIDUES

Corn residues (cobs, leaves and stalks) are abundantly available renewable materials that can be used as an energy source in gasification and combustion systems. Proper understanding of the physical properties of these materials is necessary for their use in thermochemical conversion processes. The physical properties (moisture content, particle size, bulk density and porosity) of corn cobs, leaves and stalks were determined in this study. The moisture contents were 6.38, 7.92 and 6.40% of the cobs, leaves and stalks, respectively. The cobs had the highest weight percentage (18.23%) of the small particles (0.850 mm). Most of the stalk particles (84.82%) were in the range of 0.212-0.850 mm. The cob particle size had a normal concave (inward) distribution between particle sizes 0.106 mm (18.23 weight %) and 0.925 mm (25.26 weight %) with the lowest weight percentage (5.30 weight %) at 0.390 mm particle size while the stalk particle size had a normal convex (outward) distribution between particle sizes 0.106 mm (8.49 weight %) and 0.925 mm (6.69 weight %) with the highest weight percentage (23.47 weight %) at the 0.605 mm particle size. The leaves had an increasing trend of particle size distribution between the particle sizes 0.106 and 0.925 mm. The average particle sizes for the cobs, leaves and stalks were 0.56, 0.70 and 0.49 mm, respectively. The average bulk density was 282.38, 81.61 and 127.32 kg m-3 for the corn cobs, leaves and stalks, respectively. The average porosity was 67.93, 86.06 and 58.51% for the corn cobs, leaves and stalks, respectively. A positive relationship between the average particle size and the porosity was observed for the corn residues. The differences in the physical properties among the corn residues (cobs, leaves and stalks) observed in this study are due to variations in the compositions and structures of these materials.

PHYSICAL PROPERTIES OF WHEAT STRAW VARIETIES CULTIVATED UNDER DIFFERENT CLIMATIC AND SOIL CONDITIONS IN THREE CONTINENTS

Over 500 million tonnes of wheat straw are produced annually worldwide, the majority of which are burnt in the field causing significant environmental and health problems as well as serious traffic accidents in addition to loss of a valuable resource. Wheat straw is abundantly available and renewable and can be used as an energy source in gasification and combustion systems. Proper understanding of the physical properties of wheat straw is necessary for utilizing these materials in thermochemical conversion processes. Wheat straws were collected from Egypt (Africa), Canada (North America) and Guyana (South America) and ground using medium size Wiley Mill. The physical properties (moisture content, particle size, bulk density and porosity) of wheat straws were determined using standard procedures. The moisture contents of wheat straws were in the range of 5.02-7.79%. The majority (56.87-93.36%) of the wheat straws particles were less than 0.85 mm and the average particle sizes were in the range of 0.38-0.69 mm. The average bulk density of the wheat straws were in the range of 97.52-177.23kg m-3. A negative linear relationship between the bulk density and the average particle size was observed for the wheat straws. The average porosity of the wheat straws were in the range of 46.39-84.24%. A positive linear relationship between the porosity and the average particle size for the wheat straws was also observed. The wheat straw varieties collected from different countries had different physical properties due to variations in climatic conditions, soil type and used fertilizer. Also, significant differences were observed among the varieties grown under same climatic and cultivation conditions.

Production of Activated Carbon from Cocoa (Theobroma cacao) Pod Husk

Activated carbons were obtained from cocoa pod husk using two different initial particle sizes (ranges 0.25 – 0.50mm and 0.50 – 1.00mm), three chemical activation agents (K2CO3, KOH and ZnCl2) and carbonization under nitrogen atmosphere during two hours at three different temperatures (500°C, 650°C and 800°C). The prepared activated carbons were characterized using Brunauer–Emmett–Teller (BET) and Langmuir surface areas, pore volume, average pore size, bulk density, moisture, ash content, and yield. The five best activated carbons were selected for further experiments according to the chemical activation agent used, high BET surface area, high pore volume and low ash content. Additionally, content of impurities, carbon content and FE-SEM micrographs were determined for these five best activated carbons. As adsorption tests were also carried out with these samples. Results of the experiments show that cocoa pod husk is a material that can be used to produce activated carbon by chemical activation and ZnCl2 showed to be the best chemical activation agent based on the highest BET surface area (780 m2/g in the best case) and pore volume (0.58 m3/g in the best case), the lowest ash content (6.14% in the best case), and the highest carbon content (86.1% in the best case), compared with others chemicals. Carbons activated by ZnCl2 are capable to adsorb As(V), getting As(V) removal levels up to 80% in less than 1 hour in the experimental conditions applied (initial pH 6-7, activated carbon concentration 0.1 g/l and 0.5 g/l, initial As concentration 100 ppb).

Technical Note: Durability Analysis of Large Corn Stover Briquettes

Densification of agricultural residues is a key step in a cost-effective, large-scale, biomass feedstock supply system. Lab-scale densification systems exist which can produce large-scale densified corn stover briquettes that measure between 220 and 420 mm in length and with an average bulk density of 190 kg/m3 (dry particle density of 460 kg/m3). MOG (material other than grain ) and pure cob briquettes produced similar lengths and dry particle densities of 424 kg/m3 and 421 kg/m3, respectively. Durability testing, utilizing a modified form of ASABE S269.4 (ASABE Standards, 2007) was conducted to determine the overall product quality associated with these densified briquettes. This publication describes experiments which quantified the durability or briquettes produced with different material types (corn stover, MOG, the chaff from a conventional corn harvest, and pure cobs) and material particle sizes (produced from a combine chopper, MOG, and a hammer mill with a 19-mm screen opening size). The durability rating varied with each of the main effect test parameters and produced a maximum 46% durability rating using pure cobs directly from a combine without additional size reduction. The durability rating was quite low for corn stover and MOG briquettes, and it was improved for pure cob briquettes. Biomass preprocessing in a hammermill significantly reduced durability due to a lack of fiber interaction throughout the large briquette.

Effect of Compaction on Physical and Micromorphological Properties of Forest Soils

The objective of this research was to assess the effect of skidding machinery on soil physical and micromorphological properties. The different positions (control or non-traffic areas, left wheel track, right wheel track and log track) and two soil depths (0 - 10 and 10 - 20 cm) in three repetitions were investigated. The results showed that average soil dry bulk density in four positions and two soil depths were significantly different. Comparison of average total porosity percentage and soil saturated hydraulic conductivity revealed that there were significant differences in four positions and two soil depths. Soil thin section studies using Image Tool software showed that in compacted samples there was an increase in the number of vughs voids and channels voids were in low occurrence. Micromorphological studies showed that soil compaction caused void size to decrease. In compacted samples voids bigger than 10 μm were very rare and dominant voids size was 2 μm. In compacted samples soil structure were damaged and aggregates were compressed. Also soil matrix was compressed and microstructure was massive. Results from this study confirmed that skidding machinery had a significant effect on soil physical and morphological properties. These changes causes soil and environmental degradation due to reduction in water infiltration increasing soil erosion risk.

매립가스 발생량에 따른 자원화 가능성 평가

This study was performed to the municipal waste generation amounts and characteristics for B city in Gangwon province, predicted the methane gas generation rate emitted from landfill, and analyzed the possibility of energy recovery to RDF(Refuse Derived Fuel) using combustible waste. The study results showed that the average bulk density of municipal waste for B city was 144.0 kg/, and the average ratios of combustible waste were 36.0 % of paper, 21.6 % of vinyl, and 19.7 % of food waste. respectively. In the experiment for heating value, high and low heating value(moisture) was measured to 3,471 /kg and 2,941 /kg, respectively. After the prohibition of burying of food waste in landfill, the heating value of municipal waste was dramatically increased due to increase of the ratio of paper, vinyl, and plastic waste. The prediction results of methane gas generation rate emitted from landfill showed that the gas generation rate is increasing to 2,505.7 CH4 ton/year in 2021. After then, the rate is decreasing gradually. When the RDF facility is installed, the rate is decreasing after peaking at 1,956.9 CH4 ton/year in 2013. The generation rate of LFG emitted from waste landfill of B city was analyzed to 9.92 /min, similar to 10.11 /min for other city.

Effect of carrier gas on bulk density and microstructure distribution of carbon/carbon composites fabricated by thermal gradient chemical vapor infiltration

The effect of the type of carrier gas on the bulk density and microstructure distribution of carbon/carbon (C/C) composites fabricated by thermal gradient chemical vapor infiltration from propylene was investigated. The results show that the type of carrier gas has an appreciable influence on the radial distribution of density and microstructure of the C/C composites. When N 2 is used as carrier gas, the average bulk density of the carbon disk is 1.54 g/cm 3 after 400-h infiltration, and the radial density difference of the disk is 0.24 g/cm 3. Furthermore, smooth laminar pyrolytic carbon forms at the outer wall of the disks. When H 2 is used as carrier gas, an entirely rough laminar pyrolytic carbon matrix and C/C disks with average bulk density of 1.67 g/cm 3 are obtained in the same time, and the radial density difference of the disk is only 0.11 g/cm 3. No matter which of these two carrier gases is used, the lower density zone is found to be at or near the middle of the disks.

Bidirectional transport in a multispecies totally asymmetric exclusion-process model

We study a minimal lattice model which describes bidirectional transport of "particles" driven along a one-dimensional track, as is observed in microtubule based, motor protein driven bidirectional transport of cargo vesicles, lipid bodies, and organelles such as mitochondria. This minimal model, a multispecies totally asymmetric exclusion process (TASEP) with directional switching, can provide a framework for understanding the interplay between the switching dynamics of individual particles and the collective movement of particles in one dimension. When switching is much faster than translocation, the steady-state density and current profiles of the particles are homogeneous in the bulk and are well described by mean-field (MF) theory, as determined by comparison to a Monte Carlo simulation. In this limit, we can map this model to the exactly solvable partially asymmetric exclusion-process (PASEP) model. Away from this fast switching regime the MF theory fails, although the average bulk density profile still remains homogeneous. We study the steady-state behavior as a function of the ratio of the translocation and net switching rates Q and find a unique first-order phase transition at a finite Q associated with a discontinuous change of the bulk density. When the switching rate is decreased further (keeping translocation rate fixed), the system approaches a jammed phase with a net current that tends to zero as J~1/Q. We numerically construct the phase diagram for finite Q.

Impact of changing crop rotation to continuous wheat on soil characteristics in semiarid areas

To evaluate the effect of crop rotation on soil structural properties and aggregate fractal dimension, three locations were selected in Maragheh and Hashtroud areas, northwest of Iran. Four crop rotations were implemented and several soil physical and chemical properties were evaluated. In wheat-chickpea and wheat-fallow rotation treatments (T2 and T4) average bulk density (BD) of 1.155 g cm-3 was significantly (P< 0.01) lower than continuous wheat cropping (T1) and wheat-fallow-wheat-wheat-wheat (T3) treatments with BD of 1.29 g cm-3. Water aggregate stability (WAS) in T4 became significantly (P<0.01) greater than other rotations. Saturated water content (θs) of T1 and T3 (0.39 cm3cm-3) was significantly (P< 0.01) lower than T2 and T4 (nearly equal to 0.55 cm3cm-3). The lowest saturated hydraulic conductivity (KS) of about 2.0 cm h-1 occurred in T1 and T3, and the highest (5.27 cm h-1) in T4. Soil moisture content (θm) in T2 and T4 during GS21 growth stage significantly exceeded those of T1 and T3. Biological yields in T2 and T4 were nearly equal (3.05 t ha-1) and were significantly (P< 0.05) greater than T1 and T3 (1.5 t ha-1). During growth stages of GS54 and GS87, θm and other measured properties were not significantly affected by crop rotations. It appears that substitution of wheat-follow or wheat-chickpea rotations by continuous wheat cropping would gradually degrade the soils and thus should be abandoned. Key words: Crop rotation, fractal dimension, mean weight diameter, soil structure, water aggregate stability.

FLOW AND FUNCTIONAL CHARACTERIZATION OF CORNSTARCH POWDER IN THE PRESENCE OF WATER AND PREGELATINIZED STARCH

ABSTRACTA model system comprising cornstarch has been agglomerated in the presence of binders like water and pregelatinized starch (PGS). Moisture and PGS contents have been varied between 12.3 and 20.1% and 0 and 6%, respectively. The physical characteristics of powder that have been determined include loose bulk density, wetting time and sinking time. A powder flow analyzer has been employed to determine flow characteristics like maximum force and energy for compression and decompression. An increase in moisture content and/or PGS increases average particle size and loose bulk density of agglomerates. The wet agglomerates show improved wetting and sinking times compared to dried agglomerates. Like wetting time, sinking time also decreases with an increase in moisture content meaning that these two indices behave in a similar manner. The functional properties like wetting and sinking times of powders at 18.5% moisture made with PGS are instant and only take less than 5 s.PRACTICAL APPLICATIONProcessed powdered foods frequently undergo the process of rehydration with a solvent system such as water or milk. Hence, the powder needs to be wetted quickly and thoroughly, sinking into the liquid rather than floating at the liquid surface and disperse/dissolve preferably without any lump formation. The importance of wetting time lies in the development and quality control of several food powders like milk powder, instant tea, coffee and mixes that are claimed to have instant properties. The generated data and findings, although developed on a model system, can be extrapolated to other food systems for developing new products for convenience to consumers.

Deriving forest canopy fuel parameters for loblolly pine forests in eastern Texas

Crown fires, the fastest spreading of all forest fires, can occur in any forest type throughout the world. The overall aim of this study was to estimate forest canopy fuel parameters including canopy bulk density and canopy base height for loblolly pines ( Pinus taeda L.) at the plot level using both allometric equations and CrownMass/FMAPlus software. Allometric equation results were compared with the CrownMass outputs for validation. According to our results, the calculated average canopy bulk density values, across all 50 plots, were 0.18 and 0.07 kg/m3 for the allometric equation and the CrownMass program, respectively. Lorey’s mean height approach was used in this study to calculate canopy base height at the plot level. The average height values of canopy base height obtained from the Lorey height approach was 10.6 m and from the CrownMass program was 9.1 m. The results obtained for the two methods are relatively close to each other, with the estimate of canopy base height being 1.16 times larger than the CrownMass value. This study provides a practical method for quantifying these parameters and making them directly available to fire managers. The accuracy of these parameters is very important for realistic predictions of wildfire initiation and growth.

Bulk density of small meteoroids

Aims. Here we report on precise metric and photometric observations of 107 optical meteors, which were simultaneously recorded at multiple stations using three different intensified video camera systems. The purpose is to estimate bulk meteoroid density, link small meteoroids to their parent bodies based on dynamical and physical density values expected for different small body populations, to better understand and explain the dynamical evolution of meteoroids after release from their parent bodies. Methods. The video systems used had image sizes ranging from 640 × 480 to 1360 × 1036 pixels, with pixel scales from 0.01 ◦ per pixel to 0.05 ◦ per pixel, and limiting meteor magnitudes ranging from Mv =+ 2.5 to +6.0. We find that 78% of our sample show noticeable deceleration, allowing more robust constraints to be placed on density estimates. The density of each meteoroid is estimated by simultaneously fitting the observed deceleration and lightcurve using a model based on thermal fragmentation, conservation of energy and momentum. The entire phase space of the model free parameters is explored for each event to find ranges of parameters which fit the observations within the measurement uncertainty. Results. (a) We have analysed our data by first associating each of our events with one of the five meteoroid classes. The average density of meteoroids whose orbits are asteroidal and chondritic (AC) is 4200 kg m −3 suggesting an asteroidal parentage, possibly related to the high-iron content population. Meteoroids with orbits belonging to Jupiter family comets (JFCs) have an average density of 3100 ± 300 kg m −3 . This high density is found for all meteoroids with JFC-like orbits and supports the notion that the refractory material reported from the Stardust measurements of 81P/Wild 2 dust is common among the broader JFC population. This high density is also the average bulk density for the 4 meteoroids with orbits belonging to the Ecliptic shower-type class (ES) also related to JFCs. Both categories we suggest are chondritic based on their high bulk density. Meteoroids of HT (Halley type) orbits have a minimum bulk density value of 360 +400 −900 kg m −3 . This is consistent with many previous works which suggest bulk cometary meteoroid density is low. SA (Sun-approaching)-type meteoroids show a density spread from 1000 kg m −3 to 4000 kg m −3 , reflecting multiple origins. (b) We found two different meteor showers in our sample: Perseids (10 meteoroids, ∼11% of our sample) with an average bulk density of 620 kg m −3 and Northern Iota Aquariids (4 meteoroids) with an average bulk density of 3200 kg m −3 , consistent with the notion that the NIA derive from 2P/Encke.

Tailoring the microstructure and mechanical properties of arrays of aligned multiwall carbon nanotubes by utilizing different hydrogen concentrations during synthesis

We synthesize vertically aligned arrays of carbon nanotubes (CNTs) in a chemical vapor deposition system with floating catalyst, using different concentrations of hydrogen in the gas feedstock. We report the effect of different hydrogen concentrations on the microstructure and mechanical properties of the resulting material. We show that a lower hydrogen concentration during synthesis results in the growth of stiffer CNT arrays with higher average bulk density. A lower hydrogen concentration also leads to the synthesis of CNT arrays that can reach higher peak stress at maximum compressive strain, and dissipate a larger amount of energy during compression. The individual CNTs in the arrays synthesized with a lower hydrogen concentration have, on average, larger outer diameters (associated with the growth of CNTs with a larger number of walls), but present a less uniform diameter distribution. The overall heights of the arrays and their strain recovery after compression have been found to be independent of the hydrogen concentration during growth.

Bulk Density (Scaling Factor) of 14 Hardwood Species in Arkansas

With the monetary exchange for hardwood trees and logs changing from log-scale board feet to tons, it is important that bulk density values (also called scaling factors) be developed to aid in determining the value of standing trees and logs. This study included 14 species of hardwoods and a total of 325 trees. Ten species were oak, which were divided into a red oak group (seven species) and a white oak group (three species). The red oak group had an average bulk density of 80.7 lb/ft3, and the white oak group had an average bulk density of 79.2 lb/ft3. A significant difference was found between the groups, as were significant differences between species within each group. Southern red oak (Quercus falcate) had the highest value (83.0 lb/ft3), and white oak (Quercus alba) had the lowest (77.0 lb/ft3). Three hickory types had an average bulk density of 79.4 lb/ft3. Sweetgum (Liquidambar styraciflua) had a bulk density of 78.3 lb/ft3.

농림부산물을 이용한 펠릿의 열적 특성

Biomass is considered to be a major potential fuel and renewable resource for the future. In fact, there is high potential to produce the large amount of energy from biomass around the world. In this study, to obtain basic data for practical application of agricultural and forest by-products as fuel of heating system in agriculture, agricultural and forest biomass resources were surveyed, the pelletizer with capacity of was designed and manufactured and pellets were made by the pelletizer. High heating value, ash content, etc. of pellets made of agricultural and forest by-products were estimated. Straw of rice was the largest agricultural biomass in 2009 and the total amount of rice straw converted into energy of TOE. And in 2009, amount of forest by-product converted into energy of TOE. High heating values of pellets made of stem and seed of rape, stem of oat, rice straw and rice husk were 16,034, 16,026, 16,089, 15,650, respectively. High heating values of pellets made of agricultural by-products were average 83.6% compared to that of wood pellet. Average bulk density of pellets made of stem and seed of rape, stem of oat, rice straw and rice husk was (). Ash contents of the pellets were 6.6, 7, 6.2, 5.5, 33% respectively. Rice husk pellet produced the largest ash content compared to other kinds of pellets.

Physico-chemical and sensory quality of extruded light red kidney bean ( Phaseolus vulgaris L.) porridge

A laboratory co-rotating twin-screw extruder was used to study the effect of extrusion conditions on physical, chemical, and sensory characteristics of extruded light red kidney beans ( Phaseolus vulgaris L). Raw bean flour was extruded at 25 g/100g and 36 g/100g moisture content. Other extrusion parameters were: barrel temperatures, 120 °C/105 °C (BT-1) and 130/115 °C (BT-2); screw speeds, 118 rpm (SS-1), 194 rpm (SS-2), and 253 rpm (SS-3); and feed rates of 80 and 120 g/min (FR-1 and FR-2, respectively). Extrudates were analyzed for expansion ratio (ER), bulk density (BD), water absorption index (WAI), water solubility index (WSI), and lectins, as phytohemagglutinin (PHA) activity. Sensory evaluation of bean porridge, obtained after coarsely grinding extrudates, was done to compare it to Sosuma, a traditional Rwandan porridge. Feed rate significantly influenced average ER, which was determined to be 1.22 and 1.30 for FR-1 and FR-2, respectively. Increasing moisture content from 25 g/100g to 36 g/100g significantly increased average BD. The WAI and WSI values did not show a clear trend under extrusion conditions used in this study. For all extruded samples, lectin was reduced to less than one-tenth of that in the raw beans. Sensory evaluation of bean porridge, on a 1–9 hedonic scale (1 = dislike extremely and 9 = like extremely), exhibited scores of 7.65, 7.69, 6.25, and 6.94 for color, texture, flavor, and overall acceptability, respectively.

The effects of soil density on the vegetation of the Umfolozi catchment in South Africa

The effects of soil compaction on plant productivity were studied in the dry season of September 2008 in Umfolozi catchment, South Africa. This study used 10 paired plots each measuring 20 x 20 m and 1 x 1 m quadrats randomly located within the study plots in both degraded and undegraded sites. Soil samples were collected on the outer edge of the quadrats within the study plots. Soil moisture (%) in the soil samples collected from the degraded and undegraded sites was 8.94 and 13.48%, respectively. Organic matter (%) was 3.17 and 5.46% on degraded and undegraded sites, respectively. Average soil bulk density (g/cm-3) was 0.99 g/cm-3 (CV=1.81 %) and 0.83 g/cm-3 (CV=5.02 %) on degraded and undegraded sites, respectively. Porosity was greater on undegraded sites (36.2%) than on degraded sites (34.2%). Seedling density (no/pot) was 18 seedlings per pot in soil samples collected on degraded and 10 seedlings per pot on undegraded sites. Seedling mortality (no/pot) was 17 seedlings per pot and 9 seedlings per pot in the soil samples collected on degraded and undegraded sites, respectively. Spearman rank correlation showed strong correlation between seedling density and soil compaction (r=-0.481, P<0.05). Seedling emergency density (no/pot) reached highest level on degraded sites compared to undegraded sites. Seedling mortality (no/pot) reached highest level on degraded sites. The study suggests that soil compaction and soil bulk density are critical for an efficient resource management in rangelands. Key words: Soil density, soil compaction, degraded landscapes, semi-arid areas.