scholarly journals Modeling the Filling Rate of Faeces in Ordinary Pit Latrines

2021 ◽  
pp. 32-44
Author(s):  
Ugwu Francis Ifeuzu ◽  
◽  
Prof. Agunwamba Jonah Chukwuemeka ◽  
Keyword(s):  
Environmental Factors ◽  
Shape Factor ◽  
Develop Model ◽  
Situation Models ◽  
Filling Rate ◽  
Volatile Solids ◽  
Actual Volume ◽  
Ground Conditions ◽  
Pit Latrine ◽  
Filling Characteristics

Faecal sludge deposited into the pit latrine is subject to biodegradation. The aim of this research was to develop model for the filling rate of faeces in ordinary pit latrine together with the effect of shape factor on such fillings to prepare the minds of users on the filling characteristics of the pit based on contents, usage and environmental factors. Consequently, faecal sludges sampled from 100 pits already filled were subjected to laboratory analyses for their physico-chemical and biological characteristics. Models for the actual filling rate of faeces in ordinary pit latrines were derived using BOD, COD, VS, and TS data, calibrated and verified. For a more critical situation, models were also derived for the filling rates considering pit shapes that gave the actual pit filling in comparison with the general condition. From the results, the actual filling rate was lower than those obtained using BOD, VS and TS. However, the COD gave filling rate closer to the actual filling rate than other parameters since TS could not be used to assess the filling rate of faeces in pit latrines. The pits exhibited low filling rate in terms of BOD in 2 pits. In terms of COD, the filling rate was higher compared with that of BOD. Low filling rate was observed with volatile solids and only 3 pits exhibited moderately high filling rates whereas total solids had the highest number of pits with high filling rates. The filling rates for both the square and rectangular pits increased by 26.5% from 40 – 90 ℓ/capita/year to 50 – 112 ℓ/capita/year due to the shape factor and this was above the values obtained in existing models while that of the circular pit remained the same. Reduction in pit volume and increase in filling rate by faeces was due to dead corners as a result of clogging, thereby reducing the area available for faecal infiltration into the surrounding soil. Circular pits are more stable because of the natural arching effect of the ground around the hole and there are no corners to concentrate the stresses. Pits with flat sides are much more likely to develop clogging resulting to dead corners than the circular pit. From this study, it is therefore evident that the shape of pit latrine determines the actual volume and the filling rate of faeces in pit latrine taking into consideration geological and environmental factors. Thus for optimal design, our engineers should take note of the pit shape factor. Thus, the model can be used to determine the filling rate of ordinary pit latrines considering soil characteristics, ground conditions and other favourable conditions.

scholarly journals Modeling the Filling Rate of Faeces in Ordinary Pit Latrines

2021 ◽  
Vol 1 (1) ◽  
pp. 4-15
Author(s):  
Ugwu Francis Ifeuzu ◽  
Agunwamba Jonah Chukwuemeka
Keyword(s):  
Environmental Factors ◽  
Shape Factor ◽  
Develop Model ◽  
Situation Models ◽  
Filling Rate ◽  
Volatile Solids ◽  
Actual Volume ◽  
Ground Conditions ◽  
Pit Latrine ◽  
Filling Characteristics

Faecal sludge deposited into the pit latrine is subject to biodegradation. The aim of this research was to develop model for the filling rate of faeces in ordinary pit latrine together with the effect of shape factor on such fillings to prepare the minds of users on the filling characteristics of the pit based on contents, usage and environmental factors. Consequently, faecal sludges sampled from 100 pits already filled were subjected to laboratory analyses for their physico-chemical and biological characteristics. Models for the actual filling rate of faeces in ordinary pit latrines were derived using BOD, COD, VS, and TS data, calibrated and verified. For a more critical situation, models were also derived for the filling rates considering pit shapes that gave the actual pit filling in comparison with the general condition. From the results, the actual filling rate was lower than those obtained using BOD, VS and TS. However, the COD gave filling rate closer to the actual filling rate than other parameters since TS could not be used to assess the filling rate of faeces in pit latrines. The pits exhibited low filling rate in terms of BOD in 2 pits. In terms of COD, the filling rate was higher compared with that of BOD. Low filling rate was observed with volatile solids and only 3 pits exhibited moderately high filling rates whereas total solids had the highest number of pits with high filling rates. The filling rates for both the square and rectangular pits increased by 26.5% from 40 – 90 ℓ/capita/year to 50 – 112 ℓ/capita/year due to the shape factor and this was above the values obtained in existing models while that of the circular pit remained the same. Reduction in pit volume and increase in filling rate by faeces was due to dead corners as a result of clogging, thereby reducing the area available for faecal infiltration into the surrounding soil. Circular pits are more stable because of the natural arching effect of the ground around the hole and there are no corners to concentrate the stresses. Pits with flat sides are much more likely to develop clogging resulting to dead corners than the circular pit. From this study, it is therefore evident that the shape of pit latrine determines the actual volume and the filling rate of faeces in pit latrine taking into consideration geological and environmental factors. Thus for optimal design, our engineers should take note of the pit shape factor. Thus, the model can be used to determine the filling rate of ordinary pit latrines considering soil characteristics, ground conditions and other favourable conditions.

scholarly journals Development of Models for the Rational Design of Different Shapes of Pit Latrine

2021 ◽  
Vol 1 (1) ◽  
pp. 5-12
Author(s):  
Ugwu Francis ifeuzu ◽  
Agunwamba Jonah Chukwuemeka
Keyword(s):  
Rational Design ◽  
Regression Coefficients ◽  
Design Parameters ◽  
Design Models ◽  
Actual Design ◽  
Ground Conditions ◽  
Different Shapes ◽  
Pit Latrine ◽  
Using Data ◽  
Shape And Size

Specific models for the rational design of pit latrines of different shapes and sizes are presently non-existent. What exist are general design models irrespective of the shape and size of latrine which may not give the actual design parameters needed. This research was limited to the derivation of models that will aid the design of the capacity of pit latrines of different shapes and dimensions for different population of users and under different soil formations and ground conditions. The objective of this research was to derive models for the rational design of pit latrines of different shapes using data collected from 500 different household pit latrines already filled up. Thus, models were derived for different latrine pit shapes and sizes using data collected through the administration of designed questionnaire on 500 households having pit latrines already filled up. Models were developed specifically for different latrine shapes whereas those of other researchers were generalized. These models were calibrated and verified for the rational design of pit latrines of different shapes and sizes. The regression coefficients for calibration were 0.75, 0.65, and 0.50 and for verification are 0.97, 0.98 and 0.99 for square, circular and rectangular pits respectively. The implication of this research is availability of design models for the construction of different pit latrine shapes.

scholarly journals Development of Models for the Rational Design of Different Shapes of Pit Latrine

2021 ◽  
pp. 5-12
Author(s):  
Ugwu Francis ifeuzu ◽  
◽  
Prof. Agunwamba Jonah Chukwuemeka ◽  
Keyword(s):  
Rational Design ◽  
Regression Coefficients ◽  
Design Parameters ◽  
Design Models ◽  
Actual Design ◽  
Ground Conditions ◽  
Different Shapes ◽  
Pit Latrine ◽  
Using Data ◽  
Shape And Size

Specific models for the rational design of pit latrines of different shapes and sizes are presently non-existent. What exist are general design models irrespective of the shape and size of latrine which may not give the actual design parameters needed. This research was limited to the derivation of models that will aid the design of the capacity of pit latrines of different shapes and dimensions for different population of users and under different soil formations and ground conditions. The objective of this research was to derive models for the rational design of pit latrines of different shapes using data collected from 500 different household pit latrines already filled up. Thus, models were derived for different latrine pit shapes and sizes using data collected through the administration of designed questionnaire on 500 households having pit latrines already filled up. Models were developed specifically for different latrine shapes whereas those of other researchers were generalized. These models were calibrated and verified for the rational design of pit latrines of different shapes and sizes. The regression coefficients for calibration were 0.75, 0.65, and 0.50 and for verification are 0.97, 0.98 and 0.99 for square, circular and rectangular pits respectively. The implication of this research is availability of design models for the construction of different pit latrine shapes.

Retracted Article: The feasibility of char and bio-oil production from pyrolysis of pit latrine sludge

2017 ◽  
Author(s):  
Tom Bond ◽  
Queenie Tse ◽  
Clementine L. Chambon ◽  
Paul Fennell ◽  
Geoff D. Fowler ◽  
...  
Keyword(s):  
Oil Production ◽  
Volatile Solids ◽  
Bio Oil ◽  
Retracted Article ◽  
Pit Latrine ◽  
Solids Content

Biochar production is favoured from stabilised pit latrine sludge with lower water and volatile solids content.

scholarly journals Regulation of Subsoiling Tillage on the Grain Filling Characteristics of Maize Varieties From Different Eras

2021 ◽  
Author(s):  
Li-qing WANG ◽  
Xiao-Fang YU ◽  
Ju-Lin GAO ◽  
Da-Ling MA ◽  
Liang LI ◽  
...  
Keyword(s):  
Conservation Tillage ◽  
Dry Weight ◽  
Grain Filling ◽  
The Other ◽  
Filling Rate ◽  
Appearance Time ◽  
Grain Filling Rate ◽  
Maize Varieties ◽  
Tillage Method ◽  
Filling Characteristics

Abstract Grain filling is the key stage for achieving high grain yield. Subsoiling tillage has been widely used as a conservation tillage method in the maize planting region of China. This study was conducted to explore the effects of subsoiling on the grain filling characteristics of maize varieties of different eras. Five typical maize varieties from different eras (1970s, 1980s, 1990s, 2000s and 2010s) were used as trial materials with two tillage modalities: rotation tillage and subsoiling tillage. The characteristic parameters and rate parameters of grain filling were compared and analyzed using the selected tillage modalities. The results showed that the grain filling parameters of the 2010s variety were better than those of the other varieties, and these differences mainly manifested in the filling rate parameters of the rapidly increasing and slowly increasing periods. In comparison with rotation tillage, subsoiling improved the maximum grain filling rate and the grain growth during the period of the maximum grain filling rate to different degrees. In addition, subsoiling delayed the appearance time of the maximum grain filling rate, extended the grain filling duration, and improved the mean filling rate. These differences are major reasons for the significant increase in 100-kernel dry weight at harvest for subsoiling in comparison with rotation tillage. Moreover, subsoiling enhanced the filling rate parameters during the rapidly increasing and slowly increasing periods. The filling stage filling duration and filling rate of maize varieties of different eras showed different responses to subsoiling. For example, the grain filling rate parameters of the 2010s variety during the rapidly increasing period were more sensitive to subsoiling in comparison with those of the other varieties.

scholarly journals Seed filling determines seed vigour of superior and inferior spikelets during hybrid rice (Oryza sativa) seed production

2020 ◽  
Vol 48 (2) ◽  
pp. 143-152
Author(s):  
Xiaomin Wang ◽  
Qiyuan Tang ◽  
Wenwei Mo
Keyword(s):  
Seed Production ◽  
Seed Weight ◽  
Hybrid Rice ◽  
Starch Accumulation ◽  
Rice Seed ◽  
Filling Rate ◽  
Seed Vigour ◽  
Seed Filling ◽  
Inferior Spikelets ◽  
Filling Characteristics

Growth and development of spikelets are asynchronous during hybrid rice seed production. However, knowledge is limited about the variation in seed vigour between superior and inferior spikelets. The main objective of this study was to evaluate the differences in seed vigour between superior and inferior spikelets of hybrid rice, and to explore the mechanisms associated with such variations with regards to seed filling characteristics and starch accumulation. Field experiments were conducted in 2017 and 2018, and seed vigour parameters, seed filling characteristics and starch accumulation were determined. We found that significant differences were recorded in seed vigour parameters between superior and inferior spikelets. Germination percentage (GP) and vigour index (VI) of superior spikelets were higher than that of inferior spikelets, irrespective of year or variety. Moreover, significant differences were observed in seed filling characteristics and starch accumulation between superior and inferior spikelets. Lower total starch content, amylose content and amylopectin content were recorded in inferior spikelets with low seed filling rate and long seed filling duration. Superior spikelets with high seed filling rate and short seed filling duration increased final seed weight by 23.9 and 22.3% for each variety, respectively. Therefore, these results raise the possibility that seed filling influences the starch accumulation and seed weight, and is closely associated with differences in the vigour of seeds from superior and inferior spikelets during hybrid rice seed production.

scholarly journals Regulation of subsoiling tillage on the grain filling characteristics of maize varieties from different eras

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-qing Wang ◽  
Xiao-Fang Yu ◽  
Ju-Lin Gao ◽  
Da-Ling Ma ◽  
Liang Li ◽  
...  
Keyword(s):  
Grain Yield ◽  
Grain Filling ◽  
Kernel Weight ◽  
The Other ◽  
Characteristic Parameters ◽  
Filling Rate ◽  
Grain Filling Rate ◽  
Maize Varieties ◽  
Grain Filling Duration ◽  
Filling Characteristics

AbstractGrain filling is the key stage for achieving high grain yield. Subsoiling tillage, as an effective conservation tillage, has been widely used in the maize planting region of China. This study was conducted to explore the effects of subsoiling on the grain filling characteristics of maize varieties of different eras. Five typical maize varieties from different eras (1970s, 1980s, 1990s, 2000s and 2010s) were used as experimental materials with two tillage modalities (rotation tillage and subsoiling tillage). The characteristic parameters (Tmax: the time when the maximum grouting rate was reached, Wmax: the grain weight at the maximum filling rate, Rmax: the maximum grouting rate, P: the active grouting stage, Gmean: the average grouting rate; A: the ultimate growth mass) and rate parameters (T1: the grain filling duration of the gradually increasing stage, V1: the average grain filling rate of the gradually increasing stage, T2: he grain filling duration of the rapidly increasing stage, V2: the average grain filling rate of the rapidly increasing stage, T3: the grain filling duration of the slowly increasing stage, V3: the average grain filling rate of the slowly increasing stage) of grain filling of two tillage modalities were analyzed and compared. The results showed that the filling parameters closely correlated with the 100-kernel weight were significantly different among varieties from different eras, and the grain filling parameters of the 2010s variety were better than those of the other varieties, the P and Tmax prolonged by 4.06–19.25%, 5.88–27.53% respectively, the Rmax and Gmean improved by 5.68–14.81%, 4.76–12.82% and the Wmax increased by 10.14–32.58%. Moreover, the 2010s variety helped the V2 and V3 increase by 6.49–13.89%, 4.55–15.00%. In compared with rotation tillage, the grain yield of maize varieties from different eras increased by 4.28–7.15% under the subsoiling condition, while the 100-kernel weight increased by 3.53–5.06%. Under the same contrast conditions, subsoiling improved the Rmax, Wmax and Gmean by 1.23–4.86%, 4.01–5.96%, 0.25–2.50% respectively, delayed the Tmax by 4.04–5.80% and extended the P by 1.19–4.03%. These differences were major reasons for the significant increases in 100-kernel dry weight under the subsoiling condition. Moreover, subsoiling enhanced the V2 and V3 by 0.70–4.29%, 0.00–2.44%. The duration of each filling stage and filling rate of maize varieties from different eras showed different responses to subsoiling. Under the subsoiling condition, the average filling rate of the 1970–2010s varieties were improved by 1.18%, 0.34%, 0.57%, 1.57% and 2.69%. In the rapidly increasing period, the grain filling rate parameters of the 2010s variety were more sensitive to subsoiling than those of the other varieties. The rapidly increasing and slowly increasing period are the key period of grain filling. Since the 2010s variety and subsoiling all improve the grain filling rate parameters of two periods, we suggest that should select the variety with higher grain filling rate in the rapidly increasing and slowly increasing period, and combine subsoiling measures to improve the grain filling characteristic parameters of maize in production, so as to achieve the purpose of increasing 100 grain weight and yield.

Impacts of Pit Latrine Additives on Volatile Solids and E. coli in Faecal Sludge

2018 ◽  
pp. 445-464
Author(s):  
Ednah Kemboi ◽  
Jack van de Vossenberg ◽  
Christine Hooijmans ◽  
Grover Mamani
Keyword(s):  
E Coli ◽  
Volatile Solids ◽  
Pit Latrine ◽  
Faecal Sludge

Reductionist thinking and animal models in neuropsychiatric research

2019 ◽  
Vol 42 ◽  
Author(s):  
Nicole M. Baran
Keyword(s):  
Animal Models ◽  
Mental Disorders ◽  
Environmental Factors ◽  
Neuropsychiatric Disorders ◽  
Model Organisms ◽  
Developmental Genetic ◽  
Term Study ◽  
Genetic And Environmental Factors ◽  
Mechanisms Of Plasticity

AbstractReductionist thinking in neuroscience is manifest in the widespread use of animal models of neuropsychiatric disorders. Broader investigations of diverse behaviors in non-model organisms and longer-term study of the mechanisms of plasticity will yield fundamental insights into the neurobiological, developmental, genetic, and environmental factors contributing to the “massively multifactorial system networks” which go awry in mental disorders.

The dual nature of obesity in metabolic programming: quantity versus quality of adipose tissue

2020 ◽  
Vol 134 (18) ◽  
pp. 2447-2451
Author(s):  
Anissa Viveiros ◽  
Gavin Y. Oudit
Keyword(s):  
Adipose Tissue ◽  
Environmental Factors ◽  
Maternal Obesity ◽  
Metabolic Programming ◽  
Dual Nature ◽  
Prevalence Of Obesity ◽  
Adipose Tissue Volume ◽  
Males And Females ◽  
Metabolically Healthy

Abstract The global prevalence of obesity has been rising at an alarming rate, accompanied by an increase in both childhood and maternal obesity. The concept of metabolic programming is highly topical, and in this context, describes a predisposition of offspring of obese mothers to the development of obesity independent of environmental factors. Research published in this issue of Clinical Science conducted by Litzenburger and colleagues (Clin. Sci. (Lond.) (2020) 134, 921–939) have identified sex-dependent differences in metabolic programming and identify putative signaling pathways involved in the differential phenotype of adipose tissue between males and females. Delineating the distinction between metabolically healthy and unhealthy obesity is a topic of emerging interest, and the precise nature of adipocytes are key to pathogenesis, independent of adipose tissue volume.

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