Articles

Comparative Performance of Pre-Commercial vs Existing Maize Hybrids in Zambia

/0 Comments/in /by

Maize production in Zambia has remained below the global average, with a national yield of 2,800 kg/ha compared to the world average of 5,000 kg/ha, as reported by FAO. This yield gap is mainly attributed to challenges such as pests, diseases, declining soil fertility and the use of low yielding varieties with limited resistance to pests and diseases, that are not suited to local Agro ecological conditions. To address these challenges, this study was conducted at Agri-Wind in Serenje District, Zambia, to evaluate and compare the performance of six pre-commercial maize hybrids against sixteen commercially available hybrids. A total of twenty-two maize hybrids were assessed, including six pre-commercial varieties (PV17, PV18, PV19, PV20, PV21, PV22) and sixteen commercial varieties (V1 – V16). The trial was arranged in a Randomized Complete Block Design (RCBD) with three replications. Performance evaluation focused on yield potential, insect and disease resistance, as well as distinctiveness, uniformity, and stability (DUS). Data were analyzed using ANOVA in Field Book (CIMMYT) at a 5% significance level (p = 0.05). Results indicated that V5 and PV19 were the highest-yielding hybrids, producing 5,850.70 kg/ha and 5,498.18 kg/ha, respectively. These varieties, along with PV18, showed strong resistance to Northern Leaf Blight (NLB) and Maize Streak Virus (MSV), making them promising candidates for commercial release. Although PV17 had a lower yield (3,781.05 kg/ha), it demonstrated the best resistance to NLB (score of 1.5), suggesting its potential for disease-prone areas. In contrast, PV21, which had lower yields and weaker disease resistance, was deemed less suitable for release. Generally, PV19, PV18, and PV17 emerged as the most promising pre-commercial hybrids, while V5 was recommended for high-yielding areas. In addition, the DUS analysis revealed superior characteristics in the pre-commercial hybrids, such as enhanced anthocyanin coloration and optimal growth duration, indicating their potential adaptability to local agroecological conditions.

Analytical Modelling of Resistive Load Effect on Transient Voltage and Power Output from d_33-mode Piezoelectric Vibration Energy Harvester

/in /by

This research analytically investigates the effect of resistive load on the transient performance of a -mode piezoelectric vibration energy harvester. Through normalized voltage and power analyses under varying normalized resistive loads and excitation frequencies, it is observed that the normalized voltage peaks consistently at resonance frequency, with its magnitude increasing as load resistance decreases. The normalized power, however, exhibits a maximum at an optimal load resistance that aligns with the system’s internal impedance, underscoring the significance of impedance matching for efficient energy harvesting. Transient voltage and power dynamics reveal faster energy dissipation and higher fluctuations at lower resistances, while higher resistances yield smoother but less efficient energy transfer. These findings provide crucial insights into the interplay between load resistance, transient dynamics, and power optimization, paving the way for improved design and application of piezoelectric energy harvesters in real-world systems.

Reclaiming the Land: Conflict and Resistance in Contemporary Peasant Social Movement

/in /by

This study aims to analyze the dynamics of contemporary peasant social movements, especially related to conflict and resistance in reclaiming the land. The end of the New Order era in the late 1990s in Indonesia provided space for peasants to reclaim the land for their cultivated land. Reclaiming is an effort to act of resistance, carried out by oppressed people to regain their rights such as land, water, and other natural resources, as well as other means of production fairly, to create universal prosperity for the people. This study uses a qualitative method, which was carried out by exploring and understanding the meaning of research problems by collecting data that reflects the views of participants regarding the research problem being studied. Data collection techniques were carried out through literature study, observation, and in-depth interviews with peasant and social movement members and leaders in the three research villages in West Java. The results show that reclaiming is successful when there is a political opportunity and mobilization of political network resources during conflicts and peasant resistance. In addition, the importance of the political network of urban activists and university students is used in resisting the policy regime made by the power holders.

Hull Form Optimization of Fishing Vessels by Adoption of Stern Wedge and Bilge Keel

/in /by

The most recent ships incorporate a number of significant design enhancements to improve the vessel’s seaworthiness. Bulbous bow, bilge keel, stern wedge, stern tunnel, spray rails, and others are examples. A stern wedge is a small modification of the buttock lines aft of station 19 1/2. The use of this hull design feature on small high-speed planning craft for the purpose of improved powering performance is an accepted naval architectural practice. However, its use on fishing vessels is uncommon. A bilge keel is a marine gear that reduces the tendency for a ship to roll. Hull shape modifications such as bilge keel can potentially increase safety by reducing roll motions. These enhancements have not been adopted or evaluated on fishing vessels, despite the fact that they have been employed on seagoing ships. The installation of bilge keels on fishing vessels was found to have a significant influence on the roll motion of the vessels, boosting their safety and efficiency. When compared to normal trawlers, the installation of bilge keels increased roll period by at least 40% and reduced roll amplitude by 16%.