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Agrivoltaics: a paradigm for sustainable dual land use - an overview
No full textReceived: March 12th, 2025 ; Accepted: September 1st, 2025 ; Published: September 12th, 2025 ; Correspondence: [email protected] systems is an emerging solution that combines agricultural production with photovoltaic energy generation on the same area. This paper synthesizes findings from approximately 251 peer-reviewed studies, technical reports, and real-world applications to explore the classification, benefits, and implementation of agrivoltaics systems globally. Case studies from Japan, France, Africa, and Latin America reveal yield increases above 10% for certain crops under partial shading and energy production outputs of up to 1.5 MW ha-1, depending on the panel type and configuration. The overview also examines key technological developments, such as bifacial modules and smart irrigation, which improve efficiency and resource management. Additionally, it discusses the economic, environmental, and social benefits and identifies the main barriers to widespread adoption. By evaluating current challenges and future perspectives, this overview provides a comprehensive synthesis of how agrivoltaic systems contribute to sustainable energy and food production, highlighting their global relevance, integrating emerging technologies, and emphasizing the policy frameworks that support successful deployment
Vasel põhinevate nanostruktuuride loomine päikesevalguses toimivatele fotokatalüüsrakendustele
No full textDoctoral Thesis in Engineering Sciences.Doktoritöö tehnikateaduse erialal.ABSTRACT. The development of efficient visible-light photocatalysts is crucial for advancing sustainable wastewater treatment and environmental remediation. This study explores multiphase copper nanoparticles to determine the influence of phase composition on photocatalytic performance. Nanoparticles composed of Cu₂O, Cu₃N, and metallic Cu were synthesized via a non-aqueous sol-gel route, with oleylamine controlling crystallinity, particle size, and surface chemistry. Phase composition was tuned by varying stirring time and synthesis time in the oven. Extended stirring stabilized Cu₂O through improved precursor dispersion, while longer synthesis promoted Cu₃N formation and, eventually, metallic Cu. The resulting nanoparticles were tested as free-standing powders and spin-coated films, revealing trade-offs between surface exposure, mechanical stability, and reusability. Photocatalytic tests demonstrated that Cu₃N-rich nanoparticles achieved 96% degradation of methylene blue under visible light, due to favorable crystalline size. In contrast, Cu₂O-rich samples, particularly Cu2–0.75h, exhibited optimal performance for neutral red and malachite green, reaching 82% and 94% degradation, respectively, as a result of their optical properties. Mechanistic studies confirmed that degradation occurs via reactive oxygen species, with neutral red additionally undergoing deprotonation. The novelty of this work lies in the systematic synthesis optimization, the evaluation of nanoparticles under both real sunlight and controlled solar-simulator conditions, and the demonstration of practical film deposition for reusable photocatalytic systems. This study establishes clear connections between synthesis parameters, structural properties, and catalytic performance, providing a versatile platform for sunlight-driven environmental remediation and advanced materials design.LÜHIKOKKUVÕTE. Tõhusate nähtava valguse fotokatalüsaatorite arendamine on ülioluline säästva reoveepuhastuse ja keskkonna remediatsiooni edendamiseks. Käesolev doktoritöö uurib mitmefaasilisi vasknanopartikleid, et määrata faasikoostise mõju fotokatalüütilisele aktiivsusele. Nanopartiklid, mis koosnesid Cu₂O-st, Cu₃N-st ja metallilisest Cu-st, sünteesiti veevaba sol–geeli meetodiga, kus oleüülamiin kontrollis kristallilisust, osakeste suurust ja pinnakeemiat. Faasikoostist reguleeriti ahjus segamis- ja sünteesiaega muutes. Pikem segamine stabiliseeris Cu₂O parema eelühendi hajutamise kaudu, samas kui pikem süntees soodustas Cu₃N moodustumist ja lõpuks metallilise Cu teket. Saadud nanoosakesi testiti nii pulbri kui ka õhukeste kilede kujul. Katsetulemused näitasid tasakaalu pinna kättesaadavuse, mehaanilise stabiilsuse ja taaskasutatavuse vahel. Fotokatalüütilised katsed näitasid, et Cu₃N-rikkad nanopartiklid saavutasid nähtava valguse all metüleensinise 96% lagunemise, mis tulenes nende soodsast kristallilisest suurusest. Seevastu Cu₂O-rikkad proovid, eriti Cu2–0.75h, näitasid optimaalset aktiivsust neutraalse punase ja malakiitsinise lagundamisel, saavutades vastavalt 82% ja 94% lagunemise tänu oma optilistele omadustele. Mehhanistlikud uuringud kinnitasid, et lagunemine toimub reaktiivsete hapniku liikide kaudu, kusjuures neutraalne punane läbib täiendavalt deprotonatsiooni. Käesoleva töö uudne väärtus seisneb sünteesi süsteemses optimeerimises, nanopartiklite hindamises nii tegeliku päikesevalguse kui ka kontrollitud päikesesimulaatori tingimustes ning praktilise filmikatte demonstreerimises taaskasutatavate fotokatalüütiliste süsteemide jaoks. Doktoritöö loob selged seosed sünteesi parameetrite, struktuuriomaduste ja katalüütilise aktiivsuse vahel, pakkudes mitmekülgset platvormi päikesevalguse juhitud keskkonna remediatsiooniks ja arenenud materjalide disainiks.The work in the thesis is supported by the following financings. The Estonian
State funds for the PhD, the center of Excellence project F180175TIBT “EQUiTANT”
Archimedes foundation, EMÜ bridge funding P200030TIBT, PARROT mobility
program T210013TIBT, EMÜ Astra project EMBio “Value-chain based bio-
economy”, ETAG team grant PRG2115, Horizon Europe NFFA pilot project
V220149MIEQ and the Grenoble INP-CMTC platform
Dataset for Simple and Detailed Prompts
No full textKeywords were extracted from descriptive texts from the Global Ecosystem Typology using GPT-4o and classified into five groups: Physical Features, Climate Descriptors, Vegetation Types, Cultural Descriptors and Geographic Distribution. These keywords were then assigned to their respective realms, biomes and ecosystem functional groups.Data was collected between 13 January 2025 and 18 January 2025.Estonian State fund for doctoral studies to Ghieth Alkhateeb
Parika
No full textPhytoplankton biomass, diversity and abundance in samples collected from Lake Parika during the period 1953-1996
Kilingi-Nõmme lakes
No full textPhytoplankton biomass, diversity and abundance in samples collected from Kilingi-Nõmme lakes during the period 1996-2004
Effect of zeolite, clay and peat on salt stress tolerance of lettuce (Lactuca sativa L.)
No full textReceived: January 31st, 2024 ; Accepted: April 14th, 2025 ; Published: April 16th, 2025 ; Correspondence: [email protected] present study aimed to investigate the effects of natural zeolite, clay and peat amendments on the growth and NaCl absorptions of lettuce (Lactuca sativa L.) under gradually increasing salinity. Four different growing media based on quartz sands with 10% additions of zeolite, clay and peat were tested. The worst effect of NaCl on plant biomass was evident at the highest salinity levels for zeolite applications. While adverse salinity impact on leaf and root biomass was least pronounced in treatments with peat additives. As expected, the lowest Na concentrations in plant tissues were found in the growing media supplemented with zeolite. In the case of Cl, however, it was the opposite - lettuce leaves accumulated significantly higher chloride concentrations in the zeolite variants in salinity treatments above 20 mM NaCl. In the control, clay and peat treatments, as the substrate salinity increased, the Cl level in the plant increased similarly. Adverse changes in leaf chlorophyll concentration (SPAD) and photosynthetic rate (µmol m-2 s-1) parameter appeared under salinity concentrations above 20 mM and were more pronounced in zeolite and sand substrate. According to the obtained results, peat additives can effectively mitigate the harmful effects of excessive salts by binding and immobilizing them as well as improving the water-holding capacity and nutrient availability. The study also concluded that natural zeolite successfully immobilizes cationic sodium, but the harmful effect of chlorine significantly reduced plant growth and photosynthetic performance. Clay additives to the growth medium showed the potential to reduce the adverse effects of salinity on lettuce, however, under the experimental conditions implemented, the effect was small
The effect of growth stimulants based on humic acids from Ukrainian lignite and biochar from agricultural residues on the growth and development of lettuce (Lactuca sativa)
No full textReceived: November 30th, 2024 ; Accepted: March 10th, 2025 ; Published: March 31st, 2025 ; Correspondence: [email protected] amounts of plant-based waste are generated annually in the agricultural and food industries, including straw, corn residues, nutshells, and fruit pits. Disposing of this waste often relies on basic methods that avoid further processing, presenting an urgent environmental challenge. One efficient solution is converting biomass into biochar, which serves as a soil amendment. Developing cost-effective recycling methods has become critical with the increasing scarcity and rising cost of raw materials. The Dnipro Lignite Coal Basin in Ukraine offers extensive lignite reserves, enabling the production of affordable, high-quality humates for soil enhancement. In this study, wheat and barley straw were pelletized with barley bran at a 90:10 ratio. Pyrolysis was conducted at 500 °C with a heating rate of 5 °C·min⁻¹ and a one-hour holding time. The resulting biochar was added to a lettuce cultivation substrate at a 1:10 biochar-to-peat ratio. Humic substances derived from lignite were applied in 3% and 9% aqueous solutions, and environmental conditions, such as humidity and temperature, were monitored throughout the 35-day trial. Results showed that granulated biochar increased lettuce rosette diameter by 7.5% compared to perlite substrates and by 11.6% compared to peat. Additionally, 3% humate solutions enhanced rosette diameter by 11.6% and biomass weight by 25.77%. These findings confirm that biochar from agricultural residues and lignite-derived humates effectively boost lettuce yield and quality
Process of heat treatment and changes in garlic properties
No full textReceived: January 27th, 2024 ; Accepted: April 7th, 2025 ; Published: April 15th, 2025 ; Correspondence: [email protected] paper aims to present the results of research focused on the heat treatment of garlic (Allium sativum) into black garlic. The research compared three varieties of classic kitchen garlic (Dukat, Topaz and Sabagold), grown in the Czech Republic. The course of heat treatment in a hot air dryer was investigated at 60 °C. Changes in the weight and moisture of the samples were monitored gravimetrically for 78 days. The dry matter content was measured gravimetrically after drying at 105 °C. There were certain differences between the varieties studied. The intensive decrease in water content, dry basis u (g g-1) during the first 20 days was the fastest in the Topaz variety, when it dropped below 0.4 (g g-1) after only 9 days. In the Dukat and Sabagold variety water content, wet basis w (%), from the original values w = 62 to 66% dropped below 30% within 20 days, and in the Topaz variety below 20%. Changes in the colour of garlic cloves were measured by A CM-600d spectrophotometer. During the black garlic processing, its gradual darkening occurred. Lightness L* decreased in the Dukat variety from 80.39 to 27.47, Topaz from 78.29 to 29.09 and Sabagold from 83.64 to 28.72. In all varieties, colour changes occurred. Greenness (-a*) changed from the 9th day to a redness (a*) whose saturation gradually decreased. The yellowness (b*) of all varieties also decreased significantly
Nohipalo Mustjärv
No full textPhytoplankton biomass, diversity and abundance in samples collected from Nohipalo Mustjärv during the period 1958 and 2001
Relationships between seamstresses' work stress and musculoskeletal disorders in Estonian small and medium-sized enterprises
No full textMagistritöö
Ergonoomika õppekavalUuring käsitleb tööstressi (TS) ning luu- ja lihaskonna vaevuste (LLV) levimust Eesti väikese ja keskmise suurusega õmblusettevõtete töötajate seas, analüüsib nende tegurite omavahelisi seoseid ning sekkumistegevuste vajadust TS ja LLV vähendamiseks masinõmblejate hulgas. Varasemad uurimused näitavad, et õmblejate füüsiline koormus ja psühhosotsiaalsed ohutegurid mõjutavad oluliselt töötajate heaolu. Hüpoteesiks oli, et TS ja LLV on omavahel seotud, kuid neid seoseid alahinnatakse ja ei käsitleta oluliste terviseriskidena. Uurimistöö eesmärgiks oli uurida TS ja LLV ulatust ning nende näitajate seoseid Eesti õmblussektori VKE-des ning pakkuda välja praktilisi, madala kuluga ennetusmeetmeid. Metoodika. Uuring viidi läbi Eesti VKE masinõmblejate hulgas, keda kokku on 32 töötajat. Uuringus kasutati Cornelli skeleti-lihasvaevuste küsimustikku (CMDQ, Cornell Musculo-skeletal Discomfort Questionnaire) ja Kopenhaageni psühhosotsiaalsete tegurite küsimustikku (COPSOQ-II, Copenhagen Psychossocial Questionnaire, version II), kuhu lisati juurde ESENER 2019 uuringu küsimusi. Tulemused. E-küsitlus viidi läbi juhuvalimi alusel 150 töötaja ja 29 tööandja esindaja seas. Vastamismäär töötajate hulgas oli 21% ja tööandjate seas 24%. Tööstressi hinnati mõõdukaks. Enamus töötajaid koges LLV mitmes kehapiirkonnas, millest sagedasimad olid parema randme piirkond ja alaselg. Samas leiti statistiliselt olulised seosed õmblejate stressitaseme ja LLV sümptomite vahel (p<0,05). Töötajate ja tööandjate hinnangute võrdlus näitas silmatorkavaid lahkarvamusi töökoormuse ja emotsionaalse pinge tajumisel. Tööandjad hindasid tööd rutiinseks ja stabiilseks, kuid töötajad kogesid, vastupidist: väga kõrget töötempot, suurt töökoormust ning selle ebaühtlast jaotust. Tööandjate riskihinnangus ei kajastunud tööga seotud emotsionaalsed või psühholoogilised pinged. Seevastu töötajate vastused viitasid mitmetele teguritele, mis viivad mõõduka emotsionaalse stressini. Tööandjad hindasid psühhosotsiaalsete ohuteguritega tegelemist töökeskkonnas keerukaks, kuigi nad ei pidanud vähest ohutusteadlikkust takistuseks. See viitab tööandja probleemitaju vähesusele. Uuringu tulemused kinnitasid hüpoteesi, et TS ja LLV seoseid küll tunnistatakse, kuid neid ei käsitleta olulisele terviseriskidena. Uuringus pakuti välja madala kuluga sekkumistegevusi, mille rakendamine võiks parandada töötajate tervist, vähendada haiguspäevi ja tõsta töörahulolu. Edaspidi tuleks keskenduda psühhosotsiaalsete ohutegurite ja LLV seoste teadvustamise suurendamisele ning sekkumismeetmete positiivsete mõjude hindamisele töökeskkonnas.The study explores the prevalence of work-related stress (WS) and musculoskeletal disorders (MSDs) among employees in small and medium-sized sewing enterprises (SMEs) in Estonia. It analyses the interrelation of these factors and the need for intervention measures to reduce WS and MSDs among machine sewers. Previous studies indicate that the physical workload and psychosocial risk factors of sewing machine operators significantly affect employee well-being. The research hypothesis proposed that WS and MSDs are interconnected, but these links are underestimated and not addressed as significant health risks. The objective was to investigate the extent of WS and MSDs and the relationship between these indicators in Estonia’s garment sector SMEs, and to propose practical, low-cost preventive measures.
Methodology. The study was conducted among machine sewers working in Estonian SMEs, with a total of 32 employees participating. The Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) and the Copenhagen Psychosocial Questionnaire, version II (COPSOQ-II) were used, supplemented by selected questions from the ESENER 2019 survey. Results. The e-survey was carried out using a random sample of 150 employees and 29 employer representatives. The response rate was 21% among employees and 24% among employers. Work-related stress was rated as moderate. Most employees experienced MSDs in several body areas, with the most common complaints being in the right wrist and lower back. Statistically significant correlations were found between stress levels and MSD symptoms among sewing machine operators (p<0.05). A comparison of employee and employer assessments revealed considerable discrepancies in the perception of workload and emotional strain. Employers described the work as routine and stable, while employees reported the opposite: a very high work pace, heavy workload, and uneven workload distribution. Employer risk assessments did not reflect emotional or psychological strain associated with the work. In contrast, employees reported several factors leading to moderate emotional stress. Although employers acknowledged the complexity of addressing psychosocial risks in the workplace, they did not view low safety awareness as a barrier. This suggests a limited perception of the problem on the employers’ part. The study confirmed the hypothesis that the connection between WS and MSDs is acknowledged but not treated as a significant health risk. The study proposed low-cost interventions that could improve employee health, reduce sick leave, and increase job satisfaction. Future efforts should focus on raising awareness about the relationship between psychosocial risk factors and MSDs, and on evaluating the positive impact of interventions in the work environment