scholarly journals Removal of Pathogens from Domestic Wastewater Using Small-Scale Gradual Hydroponics Planted with Duranta erecta, Addis Ababa, Ethiopia

2022 ◽  
Vol 2022 ◽  
pp. 1-9
Author(s):  
Solomon Tibebu ◽  
Abebe Worku ◽  
Kenatu Angassa
Keyword(s):  
Heterotrophic Bacteria ◽  
Addis Ababa ◽  
Control Unit ◽  
Domestic Wastewater ◽  
Experimental Unit ◽  
Small Scale ◽  
Hydroponic System ◽  
Control Units ◽  
Significant Difference ◽  
And Control

This study aimed to evaluate the treatment potential of gradual hydroponics planted with Duranta erecta in the removal of pathogens from domestic wastewater. Two experimental and control units were configured in series. Each unit contains three bioreactors and was arranged in a cascaded configuration. The two experimental units used both plant and media, but the two control units used only media to treat the wastewater. Gravel and polyester sponge were used as media. Experimental unit 1 and control unit 1 used gravel as media; however, experimental unit 2 and control unit 2 used polyester sponges as media. The experiment was operated at hydraulic retention times of 1, 3, 5, and 7 days in a continuous mode. The performance of the hydroponic system was evaluated by characterizing the influent and effluent quality using standard methods. At optimum hydraulic retention time (7 days), the average removal of experimental units 1 and 2 was 98.7% and 89.8% for heterotrophic bacteria, 96.2% and 86.8% for total coliform, and 92.9% and 84.0% for fecal coliform, respectively. Analysis of variance showed that there was a significant difference P < 0.05 between the two experimental and control units in removing pathogens, but no significant difference P > 0.05 was observed between the two experimental units and between the two control units. Heterotrophic bacteria and coliforms were satisfactorily removed from domestic wastewater via a gradual hydroponic system. Hence, the hydroponic treatment system planted with Duranta erecta has a promising potential in the removal of pathogens from domestic wastewater in developing countries including Ethiopia.

A Stimulation-Retreat Special Care Unit for Elders With Dementing Illness

1998 ◽  
Vol 10 (4) ◽  
pp. 379-395 ◽  
Author(s):  
M. Powell Lawton ◽  
Kimberly Van Haitsma ◽  
Jennifer Klapper ◽  
Morton H. Kleban ◽  
Ira R. Katz ◽  
...  
Keyword(s):  
Control Unit ◽  
Special Care ◽  
Special Care Unit ◽  
Negative Behaviors ◽  
Positive Behaviors ◽  
Control Units ◽  
Dementing Illness ◽  
And Control ◽  
Negative Attributes ◽  
Additional Stimulation

Two equivalent special care nursing home units for elders with dementing illness were randomly designated as experimental and control units for an intervention called the “stimulation-retreat” model. This model introduced a set of staffing and program changes whose purpose was to diagnose, prescribe, and apply a package of care according to individual needs for additional stimulation or relief from stimulation (“retreat”). A total of 49 experimental and 48 control unit residents completed 12 months of care and were evaluated at baseline, 6 months, and 12 months. It was hypothesized that the intervention would not affect the basic disability (cognitive and activities of daily living functions), would improve negative behaviors and observed affects, and would have maximum impact in increasing positive behaviors and affects. Over time, most functions worsened, including negative attributes and affects. Lesser decline in positive affect and increases in external engagement, however, led to the conclusion that the intervention showed a marginally significant and selective effect on positive behaviors and affect.

scholarly journals Do early trends in oak barrens fire treatment predict later outcomes? Insights from three decades of vegetation monitoring

Fire Ecology ◽  
2020 ◽  
Vol 16 (1) ◽  
Author(s):  
John B. Taft
Keyword(s):  
Species Diversity ◽  
Fire Management ◽  
Basal Area ◽  
Control Unit ◽  
Species Density ◽  
Ground Layer ◽  
Treatment Unit ◽  
Reliable Predictor ◽  
Control Units ◽  
And Control

Abstract Background Vegetation structure, species diversity, and composition have been monitored at a fire-treatment and a fire-free control unit of a dry oak barrens and woodland complex in southern Illinois, USA, over a 29-year period and five burns. The restoration hypothesis is that fire management would result in different trends for vegetation parameters of conservation interest between fire treatment and control units, that before–after differences would be greater with fire management, and that early trends provide a reliable predictor for later outcomes. This study examines effectiveness of management in achieving restoration goals and uses response to the first two burns and monitoring results over the first seven years as an estimation period to test whether early trends with fire treatment are a reliable predictor for outcomes following three additional burns over the following 22 years. Results Trends differed between fire-treatment and control units for all parameters measured, and before–after differences were greater at the fire treatment unit. However, trends at the fire-treatment unit during the estimation period were a poor predictor of later outcomes. Tree density and basal area declined more than expected while ground-layer species density, richness, diversity, and percent cover did not keep pace with expectations of increase. Trends at the control unit were more predictable; however, tree basal area declined more than expected, possibly due to an outbreak of rapid white oak mortality disease, and decline of ground-layer species density was less than predicted from the early estimation period. Conclusions Results suggested that fire alone can be effective at restoring woodland and barrens natural areas and that a fire return interval of about every four years would be optimal for maintaining composition and diversity in this specific oak barrens habitat. However, burns followed immediately by severe drought possibly can have negative interactions, resulting in declines of ground-layer species diversity.

scholarly journals Process Automation of Demineralization Plant using Delta PLC, Wonderware Intouch and Delta HMI

2019 ◽  
Vol 8 (3) ◽  
pp. 4721-4727
Keyword(s):  
Control Unit ◽  
Cost Effective ◽  
Small Scale ◽  
Centralized Control ◽  
Monitoring And Control ◽  
Process Automation ◽  
Demineralized Water ◽  
Small Scale Industry ◽  
And Control

The proposed project is to design a commercial Programming Logic Controller based automation unit with SCADA and HMI for Demineralization Unit. In Demineralization, the raw water obtained from underground and Lake is treated to meet standard as per usage. Some of the closely monitored are pH, turbidity, etc. The automation tool designed uses DELTA PLC which is interfaced to local HMI which is in-turn connected to Wi–Fi using TP– Link thus supporting Remote Monitoring and Control. For centralized control unit SCADA is used by interfacing PLC with Computer. To match the communication protocol between PLC and SCADA, OPC software called KEPServer is used. Significant improvement in quantity and quality of demineralized water can be achieved. The proposed design is cost effective as it suit for small scale industry

scholarly journals Substitution of Plastics with Organic Pots in Tree Seedlings Production for Sustainable Environmental Conservation

2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Wambui Mwangi ◽  
Samuel Kariuki ◽  
Nyambura Wagara
Keyword(s):  
Production Systems ◽  
Environmental Conservation ◽  
Small Scale ◽  
Tree Seedlings ◽  
Tree Seedling ◽  
Renewable Materials ◽  
Plant Materials ◽  
Significant Difference ◽  
Olea Europea ◽  
And Control

The Mau Forest Complex, Kenya, is the location where the study below was done with the aim of investigating if small-scale operators of tree nurseries are will to embrace and use biodegradable seedling pots. These containers include baskets made of plant fibre and bamboo tubes as well as to determine the tree species that could form a denser canopy to be used in reafforestation. This study hypothesized that biodegradable pots could promote better growth of tree seedlings and offer more environmental-friendly benefits in comparison to the extensively utilized polythene containers. Biodegradable seedling pots are options friendly to the environment compared to plastic pots commonly used in activities in the greenhouse and nurseries. The use of compostable and plantable containers based on natural and renewable materials derived from plant materials have a potential market to boost the sustainable character of current tree production systems. Three species were planted including, Hagenia abyssinica in Gatimu, Juniperus procera and Olea europea subsp. africana in Mwisho wa Lami. Basket tubes gave the highest vigor (62.429 cm) with H. abyssinica in Gatimu while bamboo (58.048cm) and control (52.667cm) did not show a significant difference at p = 0.05 level. Olea europea subsp. africana generally demonstrated higher vigor with all the applied treatments than J. procera in Mwisho wa Lami. Basket treatment gave the highest height and number of branches for the two plant species while bamboo and control treatments did not have any significant differences at p = 0.05. In this study it was found that seedling bags made from plant fibres could be adopted in tree seedling propagation to remove the synthetic plastics for sustainable environmental conservation. Hagenia abysinica was also recommended for reafforestation as it formed a quick canopy.

A Study on Fault Detection Algorithm for Motor Control Unit of Electric Vehicle

2013 ◽  
Vol 431 ◽  
pp. 226-230
Author(s):  
Dong Hyun Seo ◽  
Wae Gyeong Shin ◽  
Jong Sang No
Keyword(s):  
Motor Control ◽  
Fault Detection ◽  
Real Time ◽  
Electric Motor ◽  
Control Unit ◽  
Detection Algorithm ◽  
Control Units ◽  
Safety And Reliability ◽  
Different Characteristics ◽  
And Control

Algorithms for motor control unit in electric vehicles are being actively developed with consideration given to safety and reliability these days. Faults during driving are a critical problem that is directly linked to the safety of drivers, and studies on fault detection of control units in various situations are needed. This study investigated the faults of control units in a signal level interface with a dynamic model of drive motor and the real-time interconnection of motor control unit and HILS (hardware-in-the-loop simulation). It was found through real-time simulation that simulating the fault conditions with the sensors of motor control unit could reveal different characteristics of motor control unit. Furthermore, vehicle driving simulations with electric motor control were performed. The results of this study are expected to help the development of electric motor simulations and the evaluation of MCU and control algorithms.

scholarly journals Insights on Variance Estimation for Blocked and Matched Pairs Designs

2020 ◽  
pp. 107699862094627
Author(s):  
Nicole E. Pashley ◽  
Luke W. Miratrix
Keyword(s):  
Variance Estimation ◽  
Control Unit ◽  
Potential Outcomes ◽  
Matched Pairs ◽  
Randomized Experiments ◽  
Multiple Treatment ◽  
Variance Estimators ◽  
Control Units ◽  
Average Impact ◽  
And Control

Evaluating blocked randomized experiments from a potential outcomes perspective has two primary branches of work. The first focuses on larger blocks, with multiple treatment and control units in each block. The second focuses on matched pairs, with a single treatment and control unit in each block. These literatures not only provide different estimators for the standard errors of the estimated average impact, but they are also built on different sets of assumptions. Neither literature handles cases with blocks of varying size that contain singleton treatment or control units, a case which can occur in a variety of contexts, such as with different forms of matching or poststratification. In this article, we reconcile the literatures by carefully examining the performance of variance estimators under several different frameworks. We then use these insights to derive novel variance estimators for experiments containing blocks of different sizes.

scholarly journals Evaluation of Exclusion Netting for Coffee Berry Borer (Hypothenemus Hampei) Management

Insects ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 364
Author(s):  
Melissa A. Johnson ◽  
Samuel Fortna ◽  
Nicholas C. Manoukis
Keyword(s):  
Sex Ratio ◽  
Insect Pest ◽  
Small Scale ◽  
Hypothenemus Hampei ◽  
Labor Costs ◽  
Coffee Berry ◽  
Coffee Berry Borer ◽  
Coffee Yield ◽  
Significant Difference ◽  
And Control

Exclusion nets are increasingly being used to protect a variety of agricultural crops from insect pests as a sustainable alternative to chemical controls. We examined the efficacy of exclusion nets in controlling the world’s most damaging insect pest of coffee, Hypothenemus hampei (coffee berry borer), on two small-scale coffee farms on Hawai’i Island. We recorded microclimate data, fruit infestation, population per fruit, sex ratio, mortality by Beauveria bassiana, coffee yield and quality in four paired exclusion and control (un-netted) plots on both farms. Mean and maximum daily temperature and relative humidity were similar between treatments, while mean and maximum daily solar radiation was reduced by ~50% in exclusion plots. Green and ripe fruit from exclusion plots had significantly lower infestation compared to un-netted control plots at both farms. We observed no significant difference between exclusion and control plots in the number of CBB per fruit or the female:male sex ratio. CBB mortality was significantly higher in control relative to exclusion plots in one of the two farms. Ripe fruits harvested from exclusion plots were on average significantly heavier and wider than those from control plots; however, there was no significant difference in the average yield per tree between treatments. Lastly, coffee quality was not significantly different between control and exclusion plots. Our results suggest that with complete sanitation prior to net installation in an environment where CBB is actively circulating, exclusion netting can successfully control CBB on small-scale coffee farms without reducing coffee yield or quality, and has the potential to lower production and labor costs by eliminating the need to spray pesticides.

scholarly journals Sero-Epidemiological Study on Bovine Rota and Coronavirus in Neonatal Calves in Dairy Farms of Addis Ababa, Ethiopia

2020 ◽  
Author(s):  
Hayat Abdela Assefa ◽  
Asaminew Tesfaye ◽  
Motuma Debelo Dibaba
Keyword(s):  
Risk Factors ◽  
Large Scale ◽  
Addis Ababa ◽  
Dairy Farms ◽  
Enzyme Linked Immunosorbent Assay ◽  
Small Scale ◽  
Calf Diarrhea ◽  
Significant Difference ◽  
Coronavirus Infection ◽  
Neonatal Calves

Abstract Background: Bovine rotavirus (BRV) and coronavirus (BCoV) are most commonly associated etiologies from viral causative agents of neonatal calf diarrhea. A cross-sectional study was carried out in randomly selected dairy farms of Addis Ababa from November 2018 to April 2019 with the objectives of estimating the prevalence of bovine rota and coronavirus infection in diarrheic and non-diarrheic calves and determining the associated risk factors. A probability proportional to size sampling technique (PPS) was used and accordingly, the study involved a total of 110 calves under 30 days of age from 57 dairy herds of which 34 (59.6%), 18 (31.6%) and 5 (8.8%) were small scale, medium scale and large scale farms respectively. As well risk factors associated with herd and calves were obtained from an interview of farm owners.Results: By using sandwich enzyme-linked immunosorbent assay (ELISA) test, out of these 110 calves, 4 (3.64%) were found positive for rotavirus while only 1 (0.91%) was found positive for coronavirus infection. Data generated from both interview and laboratory investigation was analyzed using SPSS version 20. As a result, prevalence of rotavirus infection showed a significant difference (P<0.05) with respect to sex, diarrhea status, colostrum timing and consistency of diarrhea. However, prevalence of coronavirus infection showed significant difference (P<0.05) only with consistency of diarrhea.Conclusions: In conclusion, rotavirus and coronavirus infection in neonatal calves in this finding showed as there is less prevalence in dairy farms of the study area; therefore, effort should be initiated for further studies on other (infectious and non-infectious) causes of calf diarrhea in this area.

Domestic wastewater treatment with a small-scale membrane bioreactor

2006 ◽  
Vol 53 (3) ◽  
pp. 69-78 ◽  
Author(s):  
C. Abegglen ◽  
H. Siegrist
Keyword(s):  
Membrane Bioreactor ◽  
Control Strategies ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Phosphate Removal ◽  
Small Scale ◽  
First Year ◽  
Effluent Quality ◽  
Domestic Wastewater Treatment ◽  
And Control

A small-scale membrane plant for treating the domestic wastewater of a four-person household is presented. The membrane bioreactor has been in operation for 6 months and achieves elimination rates of 90, 95 and 80% for total organic carbon, chemical oxygen demand and total nitrogen, respectively. Only a small amount sludge is produced. The permeate is reused for flushing toilets and has a yellowish colour. After investigations of the effluent quality, decolourisation of the permeate, energy efficiency and control strategies in the first year, urine will be treated separately in an automated precipitation reactor where struvite is produced to improve the overall phosphate removal of the plant.

scholarly journals High Performance DC-to-AC Converter Using Snubberless H-Bridge Power Switches and an Improved DC-to-DC Converter

2021 ◽  
Vol 15 ◽  
pp. 315-333
Author(s):  
Candidus U. Eya ◽  
Ayodeji Olalekan Salau ◽  
Stephen Ejiofor Oti
Keyword(s):  
High Performance ◽  
Harmonic Distortion ◽  
Control Unit ◽  
Input Voltage ◽  
Storage Capacitor ◽  
Small Scale ◽  
Two Stage ◽  
Dc Power ◽  
Power Switches ◽  
And Control

This paper presents the analysis, modeling, simulation, and implementation of a high performance DC-to-AC (DC-AC) converter. The system comprises of a combination of DC power source, stress less DC-to-DC (DC-DC) voltage converter, two snubberless power switches, and control unit. The system is portable, has a two-stage input voltage transformation and amplification with no transformer and occupies less space unlike the classical two-stage inverter systems. In addition, the system produces a constant DC boosted voltage with less stress on both the source and DC storage capacitor which are not found in conventional converters. The proposed power electronic converter system produced the following results: pure sine voltage and current waveforms, total harmonic distortion (THD) of 4.294%, power output of 5740W, efficiency of 98.9%, power loss of 60W and fast dynamic response. The target areas of applications of the proposed converter are in medium and small scale industries.

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