Optimal sizing of a photovoltaic/energy storage/cold ironing system: Life Cycle cost approach and environmental analysis

Traditional cold ironing allows ships to shut down their auxiliary engines, during the berthing time, and to be powered by an on-shore power supply. Traditionally the energy demand is satisfied by electricity form the national grid. Alternatively, a local energy production increases the energetic self-sufficiency of the port areas and reduces the pressure on the national grid with continuous peaks of energy demand. This way the port area can be considered a microgrid, characterized by both energy producers and consumers. This paper presents an optimization model, implemented on MATLAB, to provide the best sizing for a combined photovoltaic/energy storage/cold ironing system. The ferry traffic of the port of Ancona (Italy) has been taken as case study. The proposed model returns the percentage of the energy demand covered, the interactions with the national grid, and the optimal size of the PV plant and the storage capacity basing on a Life Cycle Cost (LCC) approach. Results show that the optimal configurations are 2100 kW and 3600 kW with 5750 kWh (without and with storage system) considering lower initial and operational costs, and 3700 kW and 6400 kW with 17,350 kWh (without and with storage system) hypothesizing higher costs. All scenarios ensure an environmental saving, compared to traditional on-board diesel generators, with 87.4 % maximal CO2 reduction achieved

Optimization of the mass ratio and melting temperature of PCMs integrated in Salt Gradient Solar Ponds

Phase Change Materials (PCMs) are promising materials to increase the storage capacity of solar energy-based systems, such as Salt Gradient Solar Ponds (SGSPs), as they are characterized by a large latent heat during the solid-liquid phase change. This paper introduces an optimization study for PCM integration in SGSP, in terms of PCM mass ratio (14 %, 19 %, 28 % and 47 %) in the lower convective zone and PCM melting temperature (35 °C, 44 °C and 50 °C). Numerically, a 2D model is developed, consisting in the continuity equation as well on momentum, thermal energy and diffusion equations. In order to validate this numerical model, an experimental campaign of a parallelepiped SGSP with PCM capsules in the bottom is constructed. The latter is tested for two PCMs (RT35HC and RT44HC) and under different climatic conditions of March and June. Numerical and experimental have been compared in which the maximum average relative error does not exceed 4.62 %, which ensures a positive validation. The optimization returns that the final liquid fraction of PCM decreases both increasing the mass ratio and melting temperature. Higher mass ratios reduce the final temperature of the PCM (49.5 °C with 14 % and 42 °C with 47 % for RT35HC), and also with higher melting temperatures reduce the thermal energy stored, since the pond tends to work only as a sensible energy storage system

Effects of Double-Diffusive Convection on Calculation Time and Accuracy Results of a Salt Gradient Solar Pond: Numerical Investigation and Experimental Validation

The main aim of this study is to investigate numerically and experimentally the effects of double-diffusive convection on calculation time and accuracy results of a Salt Gradient Solar Pond (SGSP). To this end, two-numerical models are developed based on the Fortran programming language. The first one is based on energy balance neglecting the development of double-diffusive convection, while the second is two-dimensional and is based on Navier-Stokes, heat, and mass transfer equations considering the development of double-diffusive convection. The heat losses via the upper part, bottom, and vertical walls, as well as the internal heating of saltwater, are considered. In order to validate and compare both numerical models, a laboratory-scale SGSP is designed, built, and tested indoors for 82 h. Results indicate that the two numerical models developed can predict the SGSP thermal behavior with good accuracy. Furthermore, the average relative error between experimental and numerical results is around 9.39% for Upper Convective Zone (UCZ) and 2.92% for Lower Convective Zone (LCZ) based on the first model. This error reduces to about 5.98% for UCZ and 3.74% for LCZ by using the second model. Consequently, the neglect of double-diffusive convection in the SGSP modeling tends to overestimate the thermal energy stored in the storage zone by about 4.3%. Based on the calculation time analysis, results show that the second model returns a calculation time hundreds of times larger than the first one and, accordingly, an increase in computational cost

Cancer stem cell biomarkers predictive of radiotherapy response in rectal cancer: A systematic review

Background: Rectal cancer (RC) is one of the most commonly diagnosed and particularly challenging tumours to treat due to its location in the pelvis and close proximity to critical genitouri-nary organs. Radiotherapy (RT) is recognised as a key component of therapeutic strategy to treat RC, promoting the downsizing and downstaging of large RCs in neoadjuvant settings, although its therapeutic effect is limited due to radioresistance. Evidence from experimental and clinical studies indicates that the likelihood of achieving local tumour control by RT depends on the complete eradica-tion of cancer stem cells (CSC), a minority subset of tumour cells with stemness properties. Methods: A systematic literature review was conducted by querying two scientific databases (Pubmed and Scopus). The search was restricted to papers published from 2009 to 2021. Results: After assessing the quality and the risk of bias, a total of 11 studies were selected as they mainly focused on biomarkers predictive of RT-response in CSCs isolated from patients affected by RC. Specifically these studies showed that elevated levels of CD133, CD44, ALDH1, Lgr5 and G9a are associated with RT-resistance and poor prognosis. Conclusions: This review aimed to provide an overview of the current scenario of in vitro and in vivo studies evaluating the biomarkers predictive of RT-response in CSCs derived from RC patients

Preliminary assessment of a two-phase direct cooling of Lithium-Ion battery pack for e-bike mobility

Electric mobility is playing an increasingly central role in emission reduction policies to mitigate climate change effect. During the operation of electric vehicles, the batteries may be subject to high variation of the required current, which can lead to a sudden increase in the cell temperature. If this condition occurs repeatedly, there would be a reduction in battery capacity and useful life, and autonomy reduction of the electric vehicle. In the worst case, this problem can lead to the thermal runaway. Therefore, cooling of electric vehicle propulsion systems is a fundamental issue for the electric mobility development. In this article we propose an innovative cooling system using a dielectric low boiling fluid in which the batteries are directly immersed. The system was tested on an electric bicycle under real operative conditions. A special test bench was realized, consisting of a real electric bicycle, a training roller to simulate the load due to road slope and an external electric motor to simulate the pedaling of the cyclist. The results show a substantial decrease in the temperature of the cells with the proposed cooling system and there was a marked improvement in the temperature uniformity of the cells inside the battery pack

Eco Maps: A Tool to Bridge the Practice-Research Gap

The social work profession has played host to a continuing dialogue about the interplay between research and practice. Traditionally, practitioners collect data that have real-world usefulness and are relevant to the intervention process with particular clients. Researchers, on the other hand, are skilled in designing and conducting studies that result in data that can be generalized to build the profession\u27s foundation of knowledge. Data collection tools and techniques that are both relevant to practice and germane to knowledge-building are needed. This paper demonstrates the use of the eco map, a common practice tool, to collect and organize data about families, thus bridging a gap between practice and research functions

A comparison of multiple luminescence chronometers at Voordrag, South Africa

A suite of 10 samples collected from an 11 m thick colluvial sequence at Voordrag, KwaZulu-Natal, South Africa, have been used to undertake a comparison of different luminescence methods. Good agreement is found between single grain quartz optically stimulated luminescence (OSL) and single grain K-feldspar post-infrared infrared-stimulated luminescence (post-IR IRSL) ages, with the exception of the basal samples where the quartz OSL signal is saturated. Multiple grain quartz OSL consistently yields ages older than single grain OSL methods. Multiple grain feldspar ages derived from the IRSL50 signal are underestimated due to anomalous fading. A previously published radiocarbon chronology yields ages that are younger than those from single grain quartz OSL and post-IR IRSL, and this is most likely due to contamination with younger carbon. Identifying the effect of saturation on the quartz OSL signal remains challenging when quartz is dated in isolation. However, using a paired quartz/feldspar dating approach is an effective way of identifying the impact of saturation on the OSL signal

A targeted drilling and dating campaign to identify Stone Age archaeological sites before excavation in west coast southern Africa

Here we present the results of a targeted drilling campaign that facilitated a geochronological study with coarse sampling resolution inside a new cave site, Simons Cave, on the west coast of southern Africa. A combination of radiocarbon (14C) dating and optically stimulated luminescence (OSL) dating was used as a range-finder. Results confirmed preservation of Holocene and late Pleistocene sediments up to 133 ± 35 ka, overlapping with the ages of Middle Stone Age (MSA) occupations of the broader west coast region. A subsequent, systematic test- excavation at the site then embarked on a second geochronological study with a higher sampling resolution. Ultimately, the comparative study confirmed the potential of Simons Cave as a new site for the exploration of hominin occupation through the later Pleistocene and Holocene, yet raised several issues concerning the direct comparability of information deriving from drilled sediment cores and actual archaeological excavation

By the lakeshore: Multi-scalar geoarchaeology in the Turkana Basin at GaJj17, Koobi Fora (Kenya)

The Late Pleistocene archaeological record in the Turkana Basin is important for studying Homo sapiens evolution, but the record in this region is poorly documented, despite a long history of significant paleoanthropological discoveries. Ambiguity around ages and site formation processes are paramount problems. We investigated the chronometric, geological, archaeological, and paleoenvironmental context of GaJj17, a locality with an artifact-bearing deposit in the Koobi Fora region. Sedimentological facies analysis coupled with micromorphological evidence indicate the depositional environment at the site changed over time from a fluvial system to an aeolian one, forming the remnant lunate feature seen today. Caliche caps the site and likely mitigated erosion of the site during high lake stands; similar deposits (∼25 m2) are found within a 2 km radius and are archaeologically sterile. Optically stimulated luminescence dating indicates the deposit and associated artifacts and fossils were emplaced circa 52–43 thousand years ago. Small (average length ∼ 3.5 cm) flakes dominate the stone artifact assemblage and include unretouched triangular flakes on diverse raw materials indicating shared affinity with Middle and Late Pleistocene lithic toolkits elsewhere in eastern Africa. Hippopotamus, crocodiles, and fish are well-represented in the faunal assemblage, along with a small sample of terrestrial ungulate specimens. More taphonomic research to understand the accumulating agent(s) of the faunal assemblages is needed. These results contribute to our understanding of Late Pleistocene archaeological site formation processes in lacustrine contexts of the Omo-Turkana Basin

Development of a Renewable Energy Forecasting Strategy Based on Numerical Weather Prediction for the Cold Ironing System at the Port of Ancona, Italy

Received: 15 October 2024. Revised: 14 November 2024. Accepted: 30 November 2024. Available online: 31 December 2024.Since renewable energy sources have an intermittent nature, forecasting strategies are increasingly important. In parallel, ports are characterized by large energy demands, especially from berthed ships. Cold ironing systems have already been proven to reduce their environmental impact by connecting ships to the electricity grid and allowing them to switch off their auxiliary engines in port. In this work, a local energy production, consisting of photovoltaic, wind turbines, and an energy storage system, is proposed to cover the energy demand of ships. In addition, an energy forecasting strategy is presented, where the solar and wind energy potential is provided by the Weather and Research Forecasting (WRF) mesoscale model. By forecasting the energy production for the following day, the storage system can be charged from the grid at night, namely in offpeak periods, reducing the pressure on the grid in on-peak periods. The methodology is tested on the port of Ancona (Italy). Results show that energy production can directly cover 54% of energy demand, and up to 70% by adding the storage system. The forecasting strategy reduces the energy withdrawn during the daytime by 24.9% and increases that during the nighttime by 18.9%, proving the effectiveness of the proposed strategy