Minimum Bulk Density Research Articles

Development of Sweet Lime (Citrus Limetta Risso) Pomace Integrated Rice-based Extruded Product: Process Optimization

Sweet lime is rich in nutrients, but has high waste index. In the present study, efforts were delineated on development of third generation rice-based snacks integrated with pulse powder and sweet lime pomace through extrusion. Optimization of the extrusion process was done by response surface methodology for achieving the maximum possible expansion ratio, water absorption index, water solubility index, crude fibre, antioxidant capacity, protein content, overall acceptability; and simultaneously minimum bulk density, hardness and in range colour change. The developed snack had excellent nutritional, physical and sensory attributes and depicted a scintillating prospect for commercial development. The optimum values of process parameters, using RSM were: 70 % rice proportion (along with 15 % pulse powder and 15 % sweet lime pomace powder) with 12 % feed moisture content, 300 rpm screw speed and 137°C die temperature. The overall desirability was 0.62 for extruded product when optimized by RSM

Effect of Drying Methods on the Physico-chemical Characteristics and Antioxidant Capacity of Taro, Sweetpotato, Stevia and Malunggay Leaves

Fresh leaves are sensitive to high temperature so that appropriate drying method should be selected to dry leaves. This study aimed to determine the effect of drying methods on the physico-chemical characteristics and antioxidant capacity of taro (Colocasia esculenta), sweetpotato (Ipomea batatas), stevia (Stevia rebaudiana), and malunggay (Moringa oleifera) leaves. Fresh, healthy and mature leaves of taro, sweetpotato, stevia, and malunggay were subjected to solar drying, mechanical drying, and sun drying. The parameters evaluated in this study included moisture content, rehydration ratio, bulk density, water activity, total chlorophyll, antioxidant capacity, and non-enzymatic browning. Results showed that solar drying obtained the highest moisture removal capacity, rehydration ratio and water activity reduction while sun drying had the least. However, it was also with solar drying that the degree of non-enzymatic browning was the highest. Minimum bulk density was attained using solar and mechanical drying. In terms of chlorophyll content, mechanical drying had the highest. No apparent difference at p<0.05 between solar and sun drying methods was observed in terms of their effects on chlorophyll retention and antioxidant capacity. Variable effects of the different drying methods include little or no change, significant declines or enhancement of the leaves' physico-chemical and antioxidant attributes.

Effect of silica fume and solid borax waste on compressive strength of fired briquettes

It is a well-known fact that industrial solid wastes which are commonly employed in construction sector make a significant contribution in reduction of environmental pollution. In this study, solid borax waste and silica fume were used as additive materials. In the briquette compositions, 3, 5 and 10% proportions of solid borax waste and 2, 5 and 10% proportions of silica fume were used in mixtures. In order to determine material characterization, micro structure (SEM) analyses of solid borax waste and silica fume were performed besides of physical and mechanical tests. Moreover, DTG analyses were implemented to specify material’s behavior under high temperature loads. According to the test results, the values of maximum compressive strength and minimum bulk density were obtained using mixtures with proportions of 2% silica fume and 10% solid borax waste. Additionally, it was determined that the briquettes having low density and high compressive strength could be produced using aforementioned all mixtures.

Assessment of Changes in Soil Infiltration, Water-Holding Capacity, Bulk Density and Fertility Parameters under Different Tree- and Crop-Based Systems in Semiarid Alfisols

ABSTRACTField experiments were conducted to assess changes in soil infiltration, water-holding capacity (WHC), bulk density and soil fertility with 15 custard apple (CA)-based systems of T1:CA+Fingermillet; T2:CA+Fodder Maize; T3:CA+Fieldbean; T4:CA+Niger; T5:CA+Chilli; T6:CA+Cowpea; T7:CA+Foxtailmillet; T8:Fingermillet; T9:Fodder Maize; T10:Fieldbean; T11:Niger; T12:Chilli; T13:Cowpea; T14:Foxtailmillet and T15:CA in 2012 and 2013 under semiarid Alfisols at Bangalore. T2 gave the maximum CA equivalent yield (1333 kgha−1), rainwater-use efficiency (4.90 kgha−1mm−1), net returns of Rs. 52690 ha−1 and a benefit-cost ratio of 2.92. T6 gave the maximum WHC of 41.0%; an infiltration rate of 33.1 cmhr−1; a cumulative infiltration of 66.2 cm; and a minimum bulk density of 1.40 gcc−1. T6 maintained maximum soil nitrogen (N) of 259 kgha−1; phosphorus pentoxide (P2O5) of 67.9 kgha−1; and potassium oxide (K2O) of 141.5 kgha −1; while T9 gave uptake N of 102.7 kgha−1; P2O5 of 24.6 kgha−1; and K2O of 103.7 kgha−1. T6 was efficient for improving the soil physical, chemical, and biological parameters based on the study.

English

Excessive tillage in conventional agriculture systems may cause plough pan, which alters soil physical properties, and thus adversely affects the crop growth and productivity. This study was conducted to monitor the effect of different tillage practices in wheat-based cropping systems on soil physical properties, allometry and grain yield of wheat. Wheat was planted in different cropping systems (viz. fallow-wheat, rice-wheat, cotton-wheat, mungbean-wheat and sorghum-wheat with zero tillage, conventional tillage, deep tillage and on two types of beds (60/30 cm with four rows) and (90/45 cm with six rows). Interaction between different tillage practices and cropping systems had significant effect on soil bulk density and total porosity, wheat allometry and grain yield. Minimum bulk density tied with higher total porosity was recorded in both types of bed sowing followed by deep tillage. This improvement in soil physical properties caused improvement in leaf area index and duration, specific leaf area, crop growth, and net assimilation rates. As a result, the productivity of bed sown wheat was better; however, grain yield of zero tilled wheat was low due to poor crop growth and net assimilation rate. Wheat productivity was substantially low when planted after sorghum; nonetheless, and was quite high when sown after mungbean. In crux, wheat planting on beds after mungbean is the best option considering the long-term environmental sustainability of wheat-based cropping systems. © 2016 Friends Science Publishers

Process Parameters Optimization for the Manufacture of Extruded Teff-based Gluten Free Snacks

This research study was aimed to develop nutritious and sensorial acceptable teff based expanded product through optimization of extrusion process parameters. The experimental study was performed using response surface methodology face centered central composite design. Teff, maize and decorticated lentil composite flour was extruded through twin screw food extruder at different barrel temperature (120, 140, 160°C), feed moisture content (14, 17, 20%) and blend ratio BR 1 (70T:20M:10L), BR 2 (60T:25M:15L) and BR3 (50T:30M:20L) at constant screw speed (340 rpm). The physical, functional, textural and sensory characteristics of extrudates were inspected and their responses were examined. Maximum expansion ratio (4.85), maximum water absorption index (7.80), minimum hardness (13.49 N/g) and minimum bulk density (0.108 g/cm 3 )were found at 140°C barrel temperature, 14% feed moisture content with blend ratio of 60% Teff, 25% Maize and 15% Lentil (60T:25M:15L). Acceptable extrudates with added vanilla powder additive were significantly (p<0.05) better in colour, flavor, crispiness and overall acceptability. The model developed could be used for designing of extrusion process parameters in order to get extrudates with desirable characteristics.

Healthy Ready-to-Eat Expanded Snack with High Nutritional and Antioxidant Value Produced from Whole Amarantin Transgenic Maize and Black Common Bean.

The snack foods market is currently demanding healthier products. A ready-to-eat expanded snack with high nutritional and antioxidant value was developed from a mixture (70:30) of whole amarantin transgenic maize (Zea mays L.) and black common bean (Phaseolus vulgaris L.) by optimizing the extrusion process. Extruder operation conditions were: feed moisture content (FMC, 15-25%, wet basis), barrel temperature (BT, 120-170°C), and screw speed (SS, 50-240). The desirability numeric method of the response surface methodology (RSM) was applied as the optimization technique over four response variables [expansion ratio (ER), bulk density (BD), hardness (H), antioxidant activity (AoxA)] to obtain maximum ER and AoxA, and minimum BD, and H values. The best combination of extrusion process variables for producing an optimized expanded snack (OES, healthy snack) were: FMC=15%/BT=157°C/SS=238rpm. The OES had ER=2.86, BD=0.119g/cm (3) , H=1.818N, and AoxA=13,681μmol Trolox equivalent (TE)/100g, dry weight. The extrusion conditions used to produce the OES increased the AoxA (ORAC: +18%, ABTS:+20%) respect to the unprocessed whole grains mixture. A 50g portion of OES had higher protein content (7.23 vs 2.32g), total dietary fiber (7.50 vs 1.97g), total phenolic content (122 vs 47mg GAE), and AoxA (6626 vs 763μmol TE), and lower energy (169 vs 264kcal) than an expanded commercial snack (ECS=Cheetos™). Because of its high content of quality protein, dietary fiber and phenolics, as well as high AoxA and low energy density, the OES could be used for health promotion and chronic disease prevention and as an alternative to the widely available commercial snacks with high caloric content and low nutritional/nutraceutical value.

Rapid and microthermal synthesis of centimetre-sized mesoporous silica aerogel sphere by using DMSO-CO2 as solvent

Centimetre-sized mesoporous silica aerogel sphere (SAS) was synthesized via sol-gel technology by one-step aging/solvent exchange at 2MPa and using DMSO-CO2 as solvent. DMSO-CO2 solvent was obtained at 7.5MPa with CO2 fluid in autoclave. The influence of an important factor, temperature, on the SASs’ performance is briefly discussed and the optimal temperature is 4°C. Low temperature is an effective way to overcome the fragility and shrinkage of SASs. Investigations by bulk density, FTIR, BET and FE-SEM indicate that the SAS has a typical three-dimensional porous structure with pore diameter about 25.4nm, minimum bulk density 0.12g/cm3 and specific surface area as high as 1078m2/g. Due to the good properties of mesoporous, the SAS could be a promising candidate of filling materials.

三峡库区陡坡根-土复合体抗冲性能

PDF HTML阅读 XML下载 导出引用 引用提醒 三峡库区陡坡根-土复合体抗冲性能 DOI: 10.5846/stxb201501270211 作者: 作者单位: 西南大学资源环境学院,西南大学,西南大学资源环境学院,西南大学资源环境学院,西南大学资源环境学院 作者简介: 通讯作者: 中图分类号: S157 基金项目: 国家自然科学基金项目（41271291，41501288）；中央高校基本科研业务费专项项目（SWU113013，XDJK2014C103，XDJK2015C170）；国家科技支撑计划项目（2011BAD31B03）；西南大学教育教学改革研究项目（2013JY052） Root-soil system anti-scourability on steep slopes in the Three Gorges Reservoir Area Author: Affiliation: College of Resources and Environment, Southwest University,College of Resources and Environment, Southwest University,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以三峡库区已种植4a的紫花苜蓿、百喜草、狗牙根和香根草为对象，并以裸地为对照，采用改进的冲刷水槽、WinRHIZO（Pro.2004c）根系分析系统和应变控制式直剪仪，分析测定5个处理根-土复合体抗冲性能以及根系、土壤参数，以期揭示不同草本植物根系对陡坡地紫色土表土抗冲性能的强化效应。研究结果表明：与对照（裸地）相比，4种草本植物根系均能显著增强紫色土表土的抗冲性能，其中香根草根-土复合体的抗冲性能最强（为对照小区的2.75-3.58倍），而紫花苜蓿复合体的抗冲性能最弱（为对照小区1.96-2.60倍）；草本植物根长密度（RLD）和根表面积密度（RSAD）是影响陡坡下紫色土表土抗冲性能的主要因子；0.50 mm< d≤ 1.50 mm径级的根系有利于土壤抗冲性能的增强，尤其是1.00 mm< d≤ 1.50 mm径级的根系对根-土复合体的抗冲性能强化效应最大；4种草本植物根系均有利于降低土壤容重、提高土壤有机质含量和增强土壤抗剪性能；土壤粘聚力c是影响根-土复合体抗冲性能的又一主要因子，径级1.00 mm< d≤ 2.00 mm的根系则最有利于提高土壤粘聚力c。 Abstract:Grass roots can improve the soil's anti-scourability. The aim of this study was to determine the effects of the roots of different grasses on anti-scourability on steep slopes of purple soil in the Three Gorges Reservoir Area. Medicago sativa, Paspalum natatu, Cynodon dactylon, and Vetiveria zizanioides plants were planted 4 years prior to the experiment, and bare control plots were selected for soil sampling. The soil anti-scourability, root parameters (root dry weight, root length, root surface area, and root volume), soil shear strength (soil internal friction angle and cohesion), and soil chemical-physical characters (bulk density and organic matter) were measured using an improved flume scouring experiment, a root analysis system (WinRHIZO (Pro.2004c)), a direct shear test experiment, the ring method, and potassium dichromate external heating method, respectively. The results show that four species of grass roots could significantly enhance soil anti-scourability. Vetiveria zizanioides roots had the greatest effect on soil anti-scourability, as soils planted with this species exhibited anti-scourability values 2.75-3.58 times that of the control; while Medicago sativa roots had the weakest effect on soil anti-scourability, as soils planted with this species exhibited anti-scourability values 1.96-2.60 times that of the control. In the scouring experiments lasting 0-10 min, the soil anti-scourability of each plot increased over time, and these dynamic change processes can be fitted well (R2 = 0.9284-0.9691) using two polynomial (the control and Cynodon dactylon plots) and logarithmic equations (the Vetiveria zizanioides, Paspalum natatu, and Medicago sativa plots). Root length density and root surface area density were the main factors affecting soil anti-scourability, and both were significantly correlated with anti-scourability (P < 0.05), especially the root surface area density. Root length density and root surface area density of Vetiveria zizanioides roots were the highest among the different species. A dividing line was set at 2.00 mm, and when 0.00 mm < d ≤ 2.00 mm, all Vetiveria zizanioides root parameters were higher than those of Medicago sativa. When d > 2.00 mm, all Medicago sativa root parameters were higher than those of Vetiveria zizanioides. Roots whose diameters were 0.50 mm < d ≤ 1.50 mm increased soil anti-scourability, especially roots (1.00 mm < d ≤ 1.50 mm) whose parameters were significantly positively correlated with anti-scourability (P < 0.01). Four species of grass reduced the soil bulk density, increased the soil organic matter content, and enhanced the soil's anti-shear strength. The minimum soil bulk density and the maximum organic matter content were 1.42 g/cm3 and 13.41 g/kg, respectively, in Medicago sativa plots. The soil bulk density of grass plots was significantly lower than that of the control plots. The organic matter contents of the Medicago sativa, Cynodon dactylon, and Vetiveria zizanioides plots were significantly higher than those of the control plots, but there was no significant difference between the organic matter contents of the Paspalum natatu and control plots. The maximum soil internal friction (φ) and cohesion (c) values were 28.82° and 82.60 kPa, respectively, in the Vetiveria zizanioides plots. Soil internal friction and cohesion of each grass plot were significantly higher than those of the control plots. Soil cohesion (c) was another main factor enhancing soil anti-scourability, and was significantly positively correlated with anti-scourability. Roots (0.00 mm < d ≤ 0.50 mm and 1.00 mm < d ≤ 2.00 mm) were found to enhance soil cohesion, especially roots 1.00 mm < d ≤ 2.00 mm. 参考文献 相似文献 引证文献

Extrusion Process Optimization for Soy-Carrot Pomace Powder Incorporated Wheat-based Snacks

Twin screw extruder was used to develop soy-carrot pomace incorporated wheat-based nutritionally rich snacks. Different experimental combinations of extrusion process variables as die temperature, screw speed, feed moisture and wheat flour in the feed formulation of wheat, defatted soy flour and carrot pomace powder, were tried using Box-Behnken design of experiment. Response surface methodology (RSM) was used to investigate the effect of die temperature (120-180°C), screw speed (300-500 rpm), feed moisture (14-20%) and wheat flour (65-85%) with soy-carrot pomace blend in equal proportion on product responses like bulk density (BD), water absorption index (WAI), water solubility index (WSI), hardness (H), colour change (CC), and overall acceptability (OA). The extrusion process was optimized for maximum expansion ratio, water absorption index, water solubility index and overall acceptability; and minimum bulk density, hardness and colour change within the experimental range. Analysis of variance (ANOVA) revealed that among the process variables, feed moisture and wheat flour percentage in feed formulation had significantly higher effect on BD, ER, WSI, CC and OA. Die temperature was observed to have significantly lower effect on the selected responses. The optimized extrusion conditions for desired product quality had desirability of 0.729.

Soil properties and organic carbon distribution under different land uses in reclaimed sodic soils of North-West India

Land use changes have caused emission of ~20% greenhouse gases (GHGs) globally that leads to shrinkage of carbon (C)-storage in the potential areas. Soil carbon pools change rapidly in response to land use change. However, in-depth understanding of C-dynamics is needed with respect to eco-systems variability. Suitable land use systems can help in sequestering C and reduce GHGs' adverse effect. Therefore, seven land uses namely Guava (Psidium guajava), Litchi (Litchi chinensis), Mango (Mangifera indica), Jamun (Syzygium cumini), Eucalyptus (Eucalyptus tereticornis), Prosopis (Prosopis alba) and Rice–wheat cropping system were selected to study their impact on soil properties and distribution of soil organic carbon (SOC) in soil layers in a reclaimed sodic soil (Typic Natrustalf, Alfisols). Soil samples were collected up to a depth of 2m i.e. 0–0.2, 0.2–0.4, 0.4–0.6, 0.6–0.8, 0.8–1.0, 1.0–1.5 and 1.5–2.0m. Results showed that soil pH and bulk density increased with depth in all the land uses. Minimum and maximum soil pH was associated with Litchi (6.81) at 0–0.2m and Eucalyptus (9.52) at 1.5–2.0m depth, respectively. Eucalyptus recorded minimum and maximum (1.41 and 1.76Mgm−3) bulk density at 0–0.2 and 1.5–2.0m soil depth, respectively. Carbon content in passive pool along with its recalcitrant nature was increased with depth in all the land uses. Depth-wise maximum decreasing tendency of lability index in Jamun plantation (0.44 at 1.0 to 1.5m and 0.72 at 1.5 to 2.0m soil depth) reiterated more recalcitrant nature of SOC. However, overall highest SOC storage (133Mg Cha−1) as well as maximum passive pool C (76 Mg C ha-1) was maintained in Guava land use.

A Comparative Study of the Effects of Non-starch Polysaccharide Gums on Physical Properties of Single-screw Extruded Aquafeed

A factorial experimental design (5×3×2) was used to investigate the effects of non-starch polysaccharide binding agents on physical properties of single-screw extrusion. Extrusion cooking trials were performed with an ingredient blend for yellow perch, fortified with five non-starch polysaccharide binding agents including three plant-origin gums (guar, wheat gluten, carboxymethyl cellulose (CMC)) and two microbial-origin exopolysaccharide gums (xanthan and pullulan), with three levels of gum inclusion (3, 6, and 10%), and two levels of screw speed (100 and 150 rpm). Effects of the independent variables on extrudate characteristics were extensively analyzed and included density, expansion ratio, water absorption and solubility indices, pellet durability, and color. Increasing gum level from 3 to 10% led to a considerable increase in unit density of extrudates for xanthan, guar, wheat gluten, CMC, and pullulan by 39.6%, 21%, 11.4%, 30%, and 19.7%, respectively. The minimum (357 kg m-3) and maximum (607 kg m-3) bulk densities were observed for the diets produced with 6% guar at 150 rpm and 10% xanthan at 100 rpm, respectively. The mean values of expansion ratio for the diets containing exopolysaccharide gums were slightly smaller than those of the other diets. Increasing gum inclusion level increased the expansion ratio of the extrudates using xanthan, wheat gluten and pullulan but reduced the expandability of diets used guar gum; increased levels did not change the expansion ratio of extrudates containing CMC. At the highest levels of gum inclusion and screw speed, both pullulan and wheat gluten gums provided better expandability of the feed extrudate. Exopolysaccharide gums resulted in extrudates with significantly higher pellet durability and water solubility indices. Overall, the addition of 6 to 10% non-starch exopolysaccharides could improve the pellet durability of aqua feed extrudates. A future study investigating the effects of feed composition and additional extrusion processing conditions on the physical parameters of these products in aquafeeds would be appropriate.

Effect of Horticultural Land uses on Soil Properties and Organic Carbon Distribution in a Reclaimed Sodic Soil

Information on soil properties and organic carbon distribution in reclaimed sodic soils under different horticultural fruit trees as well as how organic carbon stock varies depth-wise under these land uses is very limited. Therefore, four horticultural land uses namely, guava (Psidium guajava), litchi (Litchi chinensis), mango (Mangifera indica), and jamun (Syzygium cumini) were selected to study their effect on soil properties and distribution of soil organic carbon (SOC) onto different pools of their oxidizability in a reclaimed sodic soil. Soil samples were collected up to a depth of 60 cm i.e. 0–20, 20–40 and 40–60 cm from the above land uses. Results showed that soil pHw (soil: water ratio: 1: 2) and bulk density (BD) increased with depth in all the land uses. Minimum and maximum pHw was associated with litchi (6.81) at 0–20 cm and jamun (7.73) at 40–60 cm depth of soil, respectively. Guava recorded minimum BD (1.45 Mg m−3) at 0–20 cm soil depth whereas, a maximum BD of 1.66 Mg m−3 was associated with litchi plantation at lower soil depths. Among the land uses, highest clay content (19.2%) at 0–20 cm was observed under litchi plantation followed by mango (17.3%), jamun (14.4%) and guava (13.9%). Litchi (1.49%) and mango (1.4%) recorded highest CaCO3 content at 0–20 cm soil depth. The amount of oxidizable organic C (OC) varied among the land uses, on an average, its amount was highest with guava (25.9 Mg C ha−1) followed by jamun (25.1 Mg C ha−1) = litchi (25.0 Mg C ha−1) > mango (16.5 Mg C ha−1) in surface soil. Total organic carbon (TOC) stock at surface soil in descending order was guava (28.8 Mg C ha−1) > jamun (27.3 Mg C ha−1) > litchi (25.7 Mg C ha−1) > mango (19.2 Mg C ha−1). In all the land uses, with depth increment passive pool carbon content was increased due to more physical, chemical and biochemical stabilization of organic carbon in lower depths of soil. Soils under guava plantation recorded highest SOC storage (61.0 Mg C ha−1) as well as maximum passive pool C (25.3 Mg C ha−1) up to 60 cm soil depth. Therefore, guava plants can be recommended in reclaimed sodic soils or otherwise barren degraded salt affected land for income generation to the farmers as well as environmental benefit to the mankind.

Optimization of Extrusion Process Parameters for Red Lentil-carrot Pomace Incorporated Ready-to-eat Expanded Product Using Response Surface

For optimization of extrusion process for development of red lentil-carrot pomace incorporated ready- to-eat rice based expanded product, experiments were planned in Box-Behnken design using response surface methodology. The independent process variables for extrusion were feed moisture content (14-20%), die temperature (120-180℃), screw speed (300-500 rpm) and formulation (rice flour: pulse flour; 60-80%: 10-30%) with constant proportion of carrot pomace powder (10%). Second order polynomials were used to model the extruder responses, functional and physical properties as a function of extrusion process variables. The extrusion process was optimized for maximum expansion ratio, water absorption index, overall acceptability and minimum bulk density, water solubility index, specific mechanical energy and hardness with in experimental range. The optimum extrusion process conditions obtained were 80:10:10 (rice flour: pulse flour: carrot pomace powder), 14% feed moisture content, 394 rpm screw speed and 120℃ die temperature. An analysis of variance (ANOVA) revealed that among the process variables, feed moisture content followed by screw speed had the most significant effect on all the responses; screw speed had the significantly higher effect on specific mechanical energy. The proportion of red lentil and carrot pomace in rice based expanded product was observed to have significantly lower effect on the selected responses.

Study on Pumping Conveying Capacity Characteristics of Polymer Solids in Vane Extruder

Abstract A vane extruder consists of a group of vane plasticization units that can together be considered a vane pump. During extrusion, materials in the extruder are plasticized and conveyed by positive conveying and suppressed by normal stress. A mathematical model of the pumping capacity of polymer solids in the vane extruder is established based on its structure and conveying mechanism. The minimum bulk density under atmospheric pressure and leakage coefficient in this model are obtained experimentally. Four general polymer materials are chosen to investigate the pumping conveying capacity of polymer solids in the vane extruder. The experimental results of the first vane plasticization unit show that the pumping conveying capacity increases almost linearly with the rotor velocity and is only slightly influenced by the material properties. Furthermore, the leakage coefficient increases when the temperature and velocity in the vane extrusion process are set inappropriately; this reduces the pumping conveying capacity of polymer solids in the vane extruder.

Recycling of washed olive pomace ash for fired clay brick manufacturing

Milled or micronized washed olive pomace ash was used to replace different amounts (5 and 10wt%) of clay in brick manufacture. The properties of these bricks were compared to conventional products following standard procedures. Bricks formed with ash showed a decrease of 0.13–0.16W/mK in thermal conductivity. With a minimum bulk density and bending strength of 1790–1810kgm−3, and 10–12Nmm−2, respectively, fired bricks fulfil standard requirements for clay masonry units. Milled ash performs better than micronized ash. The ash leachate is a valuable source of potassium for the manufacture of fertilizers.

English

Broken rice flour was added in proportions (75%) to equal amount of dehydrated pineapple waste pulp powder and red gram powder (12.5%) were extruded in a twin-screw extruder. The formulation was extruded at different moisture content (17-21%), screw speed (260-340 rpm) and die temperature (120-140&deg;C). The lateral expansion, bulk density, water absorption index, water solubility index, hardness and sensory characteristics were measured as responses. In the experiments, increase in barrel temperature resulted in extrudate with higher expansion, higher hardness, lower bulk density, lower WSI and higher WAI. Increasing in screw speed resulted in higher expansion, lower bulk density, higher overall acceptability and lower hardness; whereas, increasing level of moisture resulted in lower hardness, lower expansion and minimum bulk density and higher overall acceptability. In the experiment, optimization studies resulted in 132.27&deg;C of barrel temperature, 315 rpm of screw speed and 18.48% of feed moisture. Key words: Twin screw extrusion, pineapple waste pulp, response surface methodology (RSM), broken rice flour, red gram powder.&nbsp

Effect of Prolonged Irrigated Fodders on Soil Physical Properties and Agronomic Water Use Efficiency

The experiment was conducted to evaluate the effect of prolonged irrigated fodders on soil key parameters and agronomic water use efficiency. The experiment was laid-out in Randomized Complete Block design with split plot arrangement having four replications with a net subplot size of 7 m × 3 m. Treatments consisted of two crops (pearl millet and sorghum) and three irrigation levels (2, 3 and 4 numbers of irrigation). Soil parameters, i.e. organic carbon, particle density, bulk density, porosity were measured at three depth, i.e. 0-5 cm, 5-10 and 10-15 cm. Agronomic parameters were also recorded such as plant height, fresh biomass and dry biomass. The results of this study showed that the maximum fresh biomass of sorghum (27.96 Mg ha-1) and of pearl millet (28.16 Mg ha-1) was observed with treatment where three number of irrigation was applied. The maximum agronomic water use efficiency was also observed with three number of irrigation in both the crops. The minimum soil bulk density and maximum percentage of pore spaces was observed with I2 where three number of irrigation was used in case of pearl millet and sorghum.

A coupled carbon, aggregation, and structure turnover (CAST) model for topsoils

In this work, a soil carbon, aggregation, and structure turnover (CAST) model was developed based on the concept suggested by many authors in the scientific literature that macro-aggregates are formed around particulate organic matter, followed by the release of micro-aggregates. A simplified mechanistic Nitrogen model was also developed. The CAST model was evaluated by field data of cropland to set-aside conversions of Critical Zone Observatories in Greece (fine textured Mediterranean) and Iowa (coarse textured humid continental). The model was calibrated successfully to capture the carbon content and the C-to-N ratio content of the pools comprising the three aggregate types (macro-aggregates: >250μm, micro-aggregates: 53–250μm, silt–clay sized aggregates: <53μm) in both sites. The soil system reached maximum macro-aggregation/porosity and minimum bulk density after 7 and 14years of cropland to set aside conversion in Greece and Iowa, respectively, according to the model results. From then onward, macro-aggregate disruption presented a constant inter-annual variability and any further SOC increase was due to micro-aggregation resulting in the increase of bulk density and decrease of porosity towards a stable value. Sensitivity and Monte Carlo uncertainty analysis on model parameters suggested that the most uncertain state variables affected by most model parameters is the carbon mass in the silt–clay size aggregates and the silt–clay mass itself. Higher size aggregates and their carbon content as well as soil structure parameters such as porosity and bulk density do not exhibit significant sensitivity to model parameters. Validation and improvement of the CAST model could assist in revealing the primary factors determining organic matter, aggregation, and structure turnover in different ecosystems. Obtaining this capability should allow better prediction of the response of the soil system to management practices, landuse changes, and climate change in order to design and optimize the appropriate measures/practices.

Effect of various dehydration methods and storage on physicochemical properties of guava powder

Present study was carried out to assess the effect of various dehydration techniques on the guava powder, physicochemical and nutritional properties. The fruits of Allahabad safeda variety of guava were used to prepare powder by different dehydration techniques like freeze drying, tunnel drying, sun drying and vacuum drying. Lightness, redness and yellowness of guava powder in terms of L*, a*, b* values was measured. Bulk density of the various powders showed that the freeze dried powder has the minimum bulk density followed by tunnel dried. Significant differences (p vacuum dried > tunnel dried > sun dried in guava powder samples. The 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity in freeze dried guava powder was found to be 88.1 (%) percent.