901 research outputs found
Selection of an ideal mesh size for the cracking unit of a palm kernel processing plant
One of the main problems associated with cracking of palm nut is the mixture of small Tenera and the big Dura variety nuts. In general, low yield of about 40% is obtained from cracking the mixture of Dura-Tenera nuts. In cracking the mixture, most of the Tenera nuts are not cracked when a large sieve size is used. When the sieve size is small, the Dura kernels get broken, thereby affecting the quality of the processed kernel oil. Hence the objective of this work was to develop a model for selecting a suitable sieve size that can be used to crack the nut in order to increase productivity and also improve the quality of the palm kernel oil. Series of experiments carried out confirmed the need for separation of nuts before cracking and also the need to select an ideal sieve size for each type of nut. In conclusion, it was established that separating the two nut varieties before cracking led to a significant (p< 0.01) increase in cracking efficiency of up to about 90% thereby increasing the productivity by 40% and making an economic gain of GH¢ 1.07 (US$0.98, October, 2008) per every 50 kg nut processed
Effects Of Cutting Parameters On Acoustic Emission Signal Response During Drilling Of Laminated Composites Using Factorial Design Method
Factorial design has been used to study the effect of cutting parameters on acoustic emission signal response during the drilling of composite laminates. Experimental design is a strategy of planning, conducting, analyzing and interpreting experiments so that sound and valid conclusion can be drawn efficiently, and economically. In this study, effects of cutting speed, feed rate and tool diameter on the acoustic emission signal response are investigated using acoustic emission\'s energy, amplitude, root mean square and frequency responses and 23 factorial design for drilling operation. Cutting tests were performed under dry conditions. Calculated effects, standard errors at 95% confidence level, and models governing the acoustic emission response to the cutting conditions have been generated from the acoustic emission signal responses. The results revealed that, acoustic energy response has significant effects due to the cutting parameters. Hence a model can be established to relate the acoustic emission\'s energy response and the cutting parameters, and as a result monitor and control the area of delamination during the drilling process.Journal of Science & Technology (Ghana) Vol. 27 (2) 2007: pp. 98-10
Nitrogen Fixation and Yield Potential of Some Early-Maturing Cowpea (Vigna Unguiculata (L) Walp) Lines
Field experiment was conducted at Mampong Campus of the University of Education to determine the yield and nitrogen fixation potential of some cowpea lines. Nine lines plus Asontem variety were studied in a Randomized Complete Block Design with four replications. The results showed that all the lines nodulated freely with the natural rhizobia in the soil. There was significant differences (P<0.05) in the nodulation abilities of the lines. Number of nodules negatively correlated with nodule dry weight (r= -0.38) whiles the amount of nitrogen fixed positively correlated with total seed yield (r= 0.94). Line IT97K-506-1 produced the highest number of nodules per plant but did not fix the highest amount of nitrogen. Lines IT97K-566-18 and IT97K-570-18 which contained the highest amount of nitrogen (4.43 and 4.70kgN/ha) respectively in their residue also produced the highest seed yield (3.58 and 3.61t/ha) respectively. The results showed that lines IT97K-570-18 and IT97K-566-18 have high yielding potentials and N-fixing abilities and should be tested on farmers’ fields. Key words: Cowpea (Vigna unguiculata (L) Walp), Nitrogen Fixition, Anova, Soil Fertility.
Insights Into Auditory Cortex Dynamics From Non-invasive Brain Stimulation
Non-invasive brain stimulation (NIBS) has been widely used as a research tool to modulate cortical excitability of motor as well as non-motor areas, including auditory or language-related areas. NIBS, especially transcranial magnetic stimulation (TMS) and transcranial direct current stimulation, have also been used in clinical settings, with however variable therapeutic outcome, highlighting the need to better understand the mechanisms underlying NIBS techniques. TMS was initially used to address causality between specific brain areas and related behavior, such as language production, providing non-invasive alternatives to lesion studies. Recent literature however suggests that the relationship is not as straightforward as originally thought, and that TMS can show both linear and non-linear modulation of brain responses, highlighting complex network dynamics. In particular, in the last decade, NIBS studies have enabled further advances in our understanding of auditory processing and its underlying functional organization. For instance, NIBS studies showed that even when only one auditory cortex is stimulated unilaterally, bilateral modulation may result, thereby highlighting the influence of functional connectivity between auditory cortices. Additional neuromodulation techniques such as transcranial alternating current stimulation or transcranial random noise stimulation have been used to target frequency-specific neural oscillations of the auditory cortex, thereby providing further insight into modulation of auditory functions. All these NIBS techniques offer different perspectives into the function and organization of auditory cortex. However, further research should be carried out to assess the mode of action and long-term effects of NIBS to optimize their use in clinical settings
Improvements in vortex flow control design to increase sewer network flood resistance
Copyright © 2013 IWA7th International Conference on Sewer Processes and Networks (SPN7), Sheffield, UK, 28-30 August 2013Flow controls are used within the water industry to manage the flow through sewer
networks by attenuating flows at convenient or critical locations. Many sewer networks, regardless
whether the systems have a flow control installed, are predicted to become stressed in the future
due to the effects of climate change, population growth and urbanisation. This issue is compounded
by the age of the Britain’s sewerage infrastructure as well as the cost and difficulty of replacing
and upgrading the infrastructure. Statutory ‘Catchment Flood Management Plans’ have been
introduced within the United Kingdom to tackle this issue by better understanding the flow path of
flood water on a catchment scale. This paper discusses a method to maximise the use of the current
sewerage infrastructure by installing flow controls, meaning a greater volume of the sewer network
can be used for stormwater storage. This paper continues by describing a method of increasing a
sewer network’s flood resistance by using vortex flow controls with a lower design flow-rate
compared to an orifice plate. This paper then concludes by describing three case studies
demonstrating the use vortex flow controls when retrofitting sewer networks as well as the impact
of implementing the retrofit design method.EPSRCSTREAM IDCHydro Internationa
Adolescent Problem Gambling in Rural Ghana: Prevalence and Gender Differentiation
Abstract
Problem gambling among young people is now a public health challenge in sub-Saharan Africa. However, the behaviour remains understudied, particularly, among rural-dwelling young people in countries within the subregion. We aimed to estimate the 12 months prevalence of problem gambling and to describe the overall and gender differences and commonalities in personal factors and social adversities associated with problem gambling among adolescents in rural Ghana. We conducted a cross-sectional survey involving a random sample of 1101 in-school adolescents aged 10–19 years in a rural district in Eastern Ghana; we used the DSM-IV-Multiple Response-Juvenile (DSM-IV-MR-J) questionnaire to assess problem gambling during the previous 12 months. Personal lifestyle and psychosocial variables were assessed using adopted items from the 2012 WHO–Global School-based Student Health Survey. Overall, three in 10 adolescents (3 in 10 females; 4 in 10 males) in rural Ghana reported problem gambling in the previous 12 months. Female adolescents who experienced problem gambling were more likely to report family-related social adversities, while adolescent male problem gambling was associated with school-related factors and interpersonal factors outside the family context. Regardless of gender, sexual abuse victimisation was associated with three times increase in the odds of experiencing problem gambling. Relative to the prevalence of gambling among adolescents in urban contexts in other countries within sub-Saharan Africa, the estimates of problem gambling among in-school rural adolescents in Ghana are higher. Although further studies are needed to understand the nuances of the behaviour, the evidence of this study underscores the need for general and targeted health promotion, intervention and prevention efforts to mitigate the family, school, and interpersonal social adversities associated with adolescent problem gambling in rural Ghana.</jats:p
Yam Tuber Dormancy and Sprouting: The Role of Concentration Dynamics of Endogenous Gibberellic Acid
The role of endogenous gibberellic acid (GA ) in the regulation of yam (Dioscorea spp.) tuber 3 dormancy was investigated by determining the changes in the endogenous GA levels during 3 natural dormancy progression. Two Dioscorea rotundata cultivars ('Pona' and 'Labreko') and one Dioscorea alata cultivar ('CRI-Ahoɔdenfoɔ') used in these studies have varying dormancy duration. Endogenous GA levels determined for the yam tubers ranged from 1.53 – 3.05 mg/g dw 3 and 1.23 – 1.58 mg/g dw for 'Pona'; 1.53 – 3.40 mg/g dw and 1.25–1.57 mg/g dw for 'Labreko'; 1.48 – 3.62 mg/g dw and 1.28 – 1.60 mg/g dw for 'CRI-Ahoɔdenfoɔ', respectively, for the outer and inner portions. 'Pona' and 'Labreko' had dormancy break at 60 days after harvest (DAH), but at 90 DAH for 'CRI-Ahoɔdenfoɔ'. Generally, GA levels increased from harvest to the maximum 3 at 30 DAH, then declined to the minimum at 60 DAH before finally increasing again at 90 DAH for the outer portions of the yam tuber. For the inner portions of the tuber, GA levels rather 3 declined significantly to the minimum at 30 DAH, increased at 60 DAH and then decreased again at 90 DAH. GA levels in the outer portions of the tubers increased by 84-122%, 65-77% and 61- 3 65%, respectively, in 'CRI-Ahoɔdenfoɔ', 'Labreko' and 'Pona', but decreased in the inner portions by 19-23%, 24-26% and 26-28%. Essentially, higher amounts of endogenous gibberellins in yam tubers induced longer dormancy duration whereas lower amounts were indicative of dormancy termination and subsequent initiation of sprouting. 
Evaluation of some basic traits of a promising coconut hybrid: Sri Lankan green dwarf crossed to Vanuatu tall (sgd x vtt)
The Lethal Yellowing Disease locally referred to as the “Cape St Paul Wilt Disease” is the single most important disease that has devastated several hectares of coconut plantations in Ghana. Two decades of coconut screening for tolerant planting material has identified the Sri LankanGreen Dwarf crossed Vanuatu Tall (SGD x VTT) coconut hybrid as the most promising planting material in the context of disease. To provide farmers with planting material that has high disease tolerance and also good agronomic characteristics, the study compared some basic traits ofthe coconut hybrid with other important coconut varieties with the objective of determining the suitability of the SGD x VTT as alternative planting material to revamp the coconut industry in Ghana. Mean sample size of 25 palms per coconut variety under the study was analyzed using two sample t-test procedure. The study indicated that the yield performance of the SGD x VTT coconut hybrid was better than the tall coconut types including the local West African Tall (WAT) and compared favourably with the Malayan Yellow Dwarf crossed Vanuatu Tall (MYD x VTT) coconut hybrid. The good agronomic characteristics of the SGD x VTT coupled with itshigh resistance to the CSPWD proved its suitability as alternative planting material to revamp the coconut industry in Ghana
Study on Development of Dynamic Compartment Model for Estimation of Environmental Tritium Behavior at the Site of NIFS
Self-harm and suicidal behaviour in Ghana: a systematic review protocol
Introduction
Self-harm and suicidal behaviour represent major global health problems, which account for significant proportions of the disease burden in low-income and middle-income countries, including Ghana. This review aims to synthesise the available and accessible evidence on prevalence estimates, correlates, risk and protective factors, the commonly reported methods and reasons for self-harm and suicidal behaviour in Ghana.
Methods and analysis
We will conduct a systematic review reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (2009) recommendations. Regional and global electronic databases (African Journals OnLine, African Index Medicus, APA PsycINFO, Global Health, MEDLINE and PubMed) will be searched systematically up to December 2021 for observational studies and qualitative studies that have reported prevalence estimates, correlates, risk and protective factors, methods and reasons for self-harm and suicidal behaviour in Ghana. The electronic database searches will be supplemented with reference harvesting and grey literature searching in Google Scholar and ProQuest Dissertations & Theses Global for postgraduate dissertations. Only records in English will be included. The Mixed Methods Appraisal Tool (2018) will be used to assess the methodological quality of included studies. Meta-analysis or narrative synthesis or both will be used, contingent on the extent of heterogeneity across eligible observational studies.
Ethics and dissemination
Considering that this is a systematic review of accessible and available literature, we will not seek ethical approval. On completion, this review will be submitted to a peer-reviewed journal, be disseminated publicly at (mental) health conferences with focus on self-harm and suicide prevention. The important findings would also be shared with key national stakeholder groups in Ghana: Ghana Association for Suicide Prevention, Ghana Mental Health Authority, Ghana Psychological Association, Centre for Suicide and Violence Research, Accra and the Parliamentary Select Committee on Health.
Prospero registration number CRD42021234622
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