On the design of a sustainable ocean drifter for developing countries

More than fifty low and medium income countries rely on the sea for their economies. Despite its importance, there is a lack of oceanographic scientific data from these countries due to the high cost of equipment and to the running costs of measurement campaigns. In this paper we present a low-cost drifter based on a LoRa communication platform and tested in a coastal area (Gulf of Trieste). The system, built using low-cost off-the-shelf components, has at least the same performances of drifters that costs about three times as much and its operation does not require any recurring costs. The use of a LoRa allows several drifters to operate simultaneously in the same area, providing a rich and homogeneous database for the statistical post processing. The high transmission rate allows an almost instantaneous position determination, facilitating the drifter recovery for successive reuse, which essential in developing countries

The P3^3 Experiment: A Positron Source Demonstrator for Future Lepton Colliders

The PSI Positron Production (P$^3$ or P-cubed) experiment is a demonstrator for a e+ source and capture system with potential to improve the state-of-the-art e+ yield by an order of magnitude. The experiment is driven by the FCC-ee injector study and will be hosted in the SwissFEL facility at the Paul Scherrer Institute in Switzerland. This paper is an overview of the P$^3$ design at an advanced stage, with a particular emphasis on a novel e+ capture system and its associated beam dynamics. Additionally, a concept for the experiment diagnostics is presented, as well as the key points of the ongoing installation works

High-Power Test of Two Prototype X-band Accelerating Structures Based on SwissFEL Fabrication Technology

This article presents the design, construction, and high-power test of two $X$-band radio frequency (RF) accelerating structures built as part of a collaboration between CERN and the Paul Scherrer Institute (PSI) for the compact linear collider (CLIC) study. The structures are a modified 'tuning-free' variant of an existing CERN design and were assembled using Swiss free electron laser (SwissFEL) production methods. The purpose of the study is two-fold. The first objective is to validate the RF properties and high-power performance of the tuning-free, vacuum brazed PSI technology. The second objective is to study the structures' high-gradient behavior to provide insight into the breakdown and conditioning phenomena as they apply to high-field devices in general. Low-power RF measurements showed that the structure field profiles were close to the design values, and both structures were conditioned to accelerating gradients in excess of 100 MV/m in CERN's high-gradient test facility. Measurements performed during the second structure test suggest that the breakdown rate (BDR) scales strongly with the accelerating gradient, with the best fit being a power law relation with an exponent of 31.14. In both cases, the test results indicate that stable, high-gradient operation is possible with tuning-free, vacuum brazed structures of this kind

Developing a framework for a sustainable water allocation plan in the Tana river basin, Kenya

Sustainable and equitable water allocation is among the key principles of Integrated Water Resources Management (IWRM). However, developing a water allocation plan for the Tana basin, one of the most important river basins in Kenya, is all but a simple task for stakeholders and policy-makers. In fact, the increasing pressure on surface and groundwater resources and the numerous drivers of change such as population growth, climate change and new infrastructures like dams and irrigation schemes, pose a huge challenge to the allocation of water. In 2009, the Water Resources Management Authority (WRMA), which is the only governmental institution entitled to regulate water resources in the country, developed a strategy to ensure the conservation and protection of the basin as well as to guarantee the participation of the stakeholders in water resources management and governance. However, the objectives set are only partially met due to the lack of appropriate data, financial and human resources as well as institutional capacity. For this reason, WRMA, the United Nations Environment Programme (UNEP) and the relevant stakeholders are currently reviewing and improving this strategy in order to provide concrete and feasible solutions to the challenges posed by the Tana River basin. Among others, priority should be given to enhancing cooperation among the stakeholders, to empowering the Water Resources Users Associations (WRUAs), to developing sub-catchment management plans and pilot areas for water allocation along with setting the reserve quantity in order to meet the basic environmental and human needs. This thesis investigates the challenges of the Tana catchment area and the key mechanisms and principles of water allocation. It further analyzes the catchment management strategy that was developed in 2009 to regulate water resources in the Tana basin and highlights its strengths and weaknesses. Based on scientific evidence and socio-political considerations, this thesis provides recommendations for the review of the Tana Catchment Area Management Strategy. In particular, the aim is to provide stakeholders and policy-makers with feasible solutions and new ideas to ensure equitable water allocation planning among users and regions as well as providing sustainable water resources management.8