Distillate Yield Research Articles

Lightweight defect detection algorithm of tunnel lining based on knowledge distillation

Due to the influence of construction quality, engineering geology and hydrological environment, defects such as dehollowing and insufficient compaction can occur in tunnels. Aiming at the problems of complex detection model, poor real-time performance and low accuracy of the current tunnel lining defect detection methods, the study proposes a lightweight defect detection algorithm of tunnel lining based on knowledge distillation. Firstly, a high-precision teacher model based on yolov5s was constructed by constructing a C3CSFM module that combines residual structure and attention mechanism, a MDFPN network structure with multi-scale feature fusion and a reweighted RWNMS re-screening mechanism. Secondly, in the distillation process, the feature and output dimension results are fused to improve the detection accuracy, and the mask feature relationship is learned in the space and channel dimension to improve the real-time detection. Tests on the tunnel lining radar defect image dataset showed that the number of parameters of the improved model was reduced from 16.03 MB to 3.20 MB, a reduction of 80%, and the average accuracy was improved from 83.4 to 86.5%, an increase of 3.1%. On the basis of maintaining the structure and detection performance of the model, the lightweight degree of the model is greatly improved, and the high-precision and real-time detection of tunnel lining defects is realized.

Performance enhancement of double slope solar still using cylindrical fins: Experimental and numerical analysis

This study explores the enhancement of a double slope solar still (DSSS) by integrating cylindrical fins on the absorber plate to improve heat transfer efficiency and water productivity. The experimental setup, made from galvanized iron sheets and insulated with a wooden box, features a glass cover angled at 34° for optimal solar radiation absorption. Testing was conducted in Gabes, Tunisia, evaluating solar radiation, wind speed, ambient temperature, and water productivity. Measurements were taken from 9:00 a.m. to 6:00 p.m., focusing on distillate yield, temperatures, and heat transfer coefficients. Both experimental and numerical analyses examined the effect of fin diameter on temperature distribution, heat transfer coefficients, and energy efficiency. Results demonstrate that the addition of fins significantly enhances both absorber and water temperatures, with the largest fin diameter (80 mm) achieving a 14.07 % increase. A validated Computational Fluid Dynamics (CFD) model showed a maximum temperature deviation of less than 3.5 °C from experimental data. The study recorded a peak energy efficiency of 71.03 % and a cumulative water productivity of 3252.55 mL/m2.

Evaluation of Modified Conventional Still Distiller Using Coupled External Passive Condenser: An Experimental Study

Solar radiation plays an important part in the desalination of saline water owing to its abundance in areas with potable water shortage and it also occupies a paramount place in green energy generation due to its simplicity of application. Still distiller is viewed by researchers as a suitable source of potable water because of low cost of fabrication, easy operation and zero emission technology. Studies by researchers are geared towards exploring new models to improve the productivity of solar stills and enhance its production rate is ongoing. The main aspiration of this work is to experiment the consequence of introducing a passive condenser to a modified conventional solar still to enhance its productivity yield. It was observed that the modified passive still distiller coupled with the external condenser gave about 11.85% higher production yield in comparison with the modified conventional still distiller. Daily and accumulated distillate yield for the still distillers have been studied and analyzed. The result of the findings revealed that sawdust padding around the still distillers is recommended to maximize productivity leading to efficient water distillation in regions where that require still distiller usage. This recommendation has been seen to produce the desired result in accessing to potable water within areas where water scarcity prevails. This is suggested to contribute effectively bearing the cost ineffective water desalination technique.

Enhancing conical solar stills with aluminum ball energy storage: Optimal distance for improved performance

The aim of this investigation is to ascertain the optimal arrangement of aluminum spheres, each with a consistent diameter of 2 cm, to serve as a cost-efficient means of energy storage for augmenting the efficacy of conical solar distillation apparatus. For this purpose, three identical conical stills were manufactured. Experimental procedures were conducted over a two-day timeframe. Initially, on the first day, the first distiller operated without any aluminum spheres, while the second and third distillers were equipped with aluminum spheres positioned at intervals of 3 cm and 4 cm, respectively. Subsequently, on the second day, the initial distillation process did not involve the presence of aluminum spheres. Nevertheless, in subsequent distillations, aluminum spheres were introduced near the base of the vessel, with respective spacings of 5 cm and 6 cm for the second and third distillations. Throughout the experiment, the brine within the vessels maintained a depth of 2 cm. The investigation revealed that the highest distillation productivity, measured at 8400 g/m^2, was attained when employing aluminum spheres with a diameter of 2 cm and spaced 3 cm apart. In contrast, distillation yields were diminished when aluminum spheres were spaced at intervals of 4, 5, and 6 cm, as well as in the absence of aluminum spheres, resulting in yields of 7750, 7200, 6700, and 5750 g/m^2, respectively. The optimal separation distance between the aluminum spheres was determined to be 3 cm, resulting in a significant enhancement of 46.08 %. Ultimately, the utilization of conical solar stills coupled with aluminum spheres as an economical energy storage medium, featuring aluminum spheres with a diameter of 2 cm and spaced 3 cm apart, emerges as the most efficacious option.

Optimizing cord pyramid solar distillers: A comprehensive study on square baffles, reflectors, and phase transition materials

Limited access to safe drinking water is a critical global issue, particularly in areas with inadequate infrastructure. Solar stills offer a promising alternative for such regions. This study investigates the influence of square baffles within a modified solar still design on its overall efficiency. Additionally, the integration of reflectors is explored to enhance both evaporation and condensation rates. Furthermore, the effectiveness of a paraffin wax phase change material (PCM) combined with silver nanoparticles is assessed within the modified still. Thermo-economic analyses are conducted to evaluate the economic feasibility of the proposed system. The findings demonstrate a significant improvement in distillation yield. The modified still with square baffles achieved a yield of 9800 mL/m2.day compared to 3550 mL/m2.day for the reference still, representing a 193 % increase. Moreover, incorporating the nano-PCM at an optimal configuration (25 cords) resulted in a further 265 % productivity increase for the modified still with both square baffles and reflectors. This configuration also achieved an efficiency of 63 %. Economic analysis revealed a minimal cost difference between the reference still (0.014 $/L) and the modified still with square baffles and nano-PCM (0.01 $/L). In terms of environmental impact, the modified still exhibited a lower annual CO2 emission of 28.8 tons.

Performance analysis of triple basin solar still with energy-exergy analysis approach

An experimental investigation was conducted on novel design of triple basin solar still with different modification in the climatic conditions of India. The triple basin solar still was modified with attachments of evacuated tubes (ETCs), heat pipes (HP), corrugated surfaces and energy storage materials called modified triple basin solar still (MTBSS). To get the more water in distillate output and higher water temperature solar still was designed with three basin area. From experimental results it was found that the total distillate output obtained by MTBSS during day and night was 16.46 l/m2 and 7.40 l/m2, respectively. The performance of MTBSS was also check by 4E (Energy, Exergy, Exergo-Economic, Exergo-Environmental) analysis for economical and environmental point of view. The generation of exergy for evaporation (Exe,bw-ig) and convection (Exc,bw-ig) for MTBSS (Modified triple basin solar still) were 24.03 & 1.30 (joule) respectively. The values of energy efficiency (ƞenergy) and exergy efficiency (ƞexergy) obtained for MTBSS were 31.89% & 3.04% respectively. An economic point of view, the CPL of water remains higher in MTBSS. The NPBT for MTBSS was 2.5 months. For environmental assessment, the CO2 mitigation for MTBSS was 0.48 t/year, based on the exergy approach. The additions of ETCs, H.P, corrugated surface, and ESMs with MTBSS are effective from an exergo-economic and carbon credit point of view.

Transforming Petrochemical Processes: Cutting-Edge Advances in Kaolin Catalyst Fabrication

The depletion of conventional light petroleum reserves has intensified the search for alternative sources, notably, low-quality heavy oils and byproducts from heavy crude processing, to meet the global demand for fuels, energy, and petrochemicals. Heavy crude oil (HO) and extra heavy crude oil (EHO) represent nearly 70% of the world’s reserves but require extensive upgrading to satisfy refining and petrochemical specifications. Their high asphaltene content results in elevated viscosity and reduced API gravity, posing significant challenges in extraction, transportation, and refining. Advanced catalytic approaches are crucial for efficient asphaltene removal and the conversion of heavy feedstocks into valuable light fractions. Kaolin, an aluminosilicate mineral, has emerged as a key precursor for zeolite synthesis and a promising catalyst in upgrading processes. This article provides a comprehensive exploration of kaolin’s geological origins, chemical properties, and structural characteristics, as well as the various modification techniques designed to improve its catalytic performance. Special focus is given to its application in the transformation of heavy crudes, particularly in facilitating asphaltene breakdown and enhancing light distillate yields. Finally, future research avenues and potential developments in kaolin-based catalysis are discussed, emphasizing its vital role in addressing the technological challenges linked to the growing reliance on heavier crude resources.

Improving the efficiency and productivity of solar distillation by creative design and heater and baffle integration

The hemispherical solar still (HSS) is a simple device used to desalinate saline water, but it has low productivity. This study aimed to enhance the evaporation rate of a hemispherical solar still (HSS) through several design modifications. The main innovation involved integrating an upper absorber with hanging wick cords, creating a modified system called the cords wick hemispherical solar still (CWHSS). Additionally, electric heaters powered by photovoltaic panels were incorporated to further boost performance, along with the introduction of squared baffles inside the CWHSS. Experimental results showed that the highest efficiency was achieved with the CWHSS incorporating baffles, heaters, and a condenser (CWHSS-B), leading to a 258% increase in distillate output and a 66.5% thermal efficiency. Under optimal conditions, the distillation rates were 4000 mL/m²/day for the HSS and 14,300 mL/m²/day for the CWHSS-B with heaters. Furthermore, the cost of water treatment was calculated at $0.022 per liter for the HSS and $0.016 per liter for the CWHSS-B, indicating significant cost benefits with the modified design.

Impact of jute covered hemispherical cups on the performance augmentation of a single slope solar still; An experimental investigation

In this article, an experimental endeavour has been reported to enhance the performance of single slope solar still by placing jute-covered hemispherical plastic cups in the water. The logic behind the augmentation is that the jute causes capillary action, due to which a thin film of water forms on the surface of the jute. The plastic cups will act as heat insulation, which will try to block the heat from going to the basin water, hence resulting in heat localization and quick evaporation of thin water film. It has been observed that this adaptation has increased overall distillate output of the single slope solar still by 36.2%. The modified still performs best till 14:00 h due to high solar insolation. In the afternoon hours, the reduction of solar radiation adversely impacts its performance in comparison to the conventional single slope solar still. The overall cost of the distillate due to the augmentation of the jute-covered hemispherical plastic cups has been reduced by 24.34% in comparison to the conventional solar still.

Enhancing pyramid solar still performance using suspended v-steps, reflectors, Peltier cooling, forced condensation, and thermal storing materials

This work aims at enhancing the thermal efficiency of pyramid distiller solar still (PDSS). A modified version (MPDSS) was developed, featuring suspended v-steps on the vertical walls of the distiller. Additionally, the MPDSS was equipped with external reflectors (MPDSS-R) designed to concentrate solar energy, thereby potentially increasing evaporation rates. To further boost the condensation rate, three different methods were implemented and evaluated independently: an external condensation unit integrated with the MPDSS (MPDSS-C), a fixed nano-enhanced thermal storing material (NTSM) within the MPDSS (MPDSS-NTSM), and an installed Peltier device (MPDSS-P). The results indicated that the MPDSS with suspended steps achieved a significant improvement, with a 40 % increase in distillate yield over PDSS. MPDSS with reflectors resulted in a 96 % increase in yield. Moreover, integrating a Peltier device with the MPDSS led to a 148 % boost in distillate yield, while the yields increased by 139 % and 143 % when utilizing the NTSM and the condenser, respectively. Consequently, the optimal performance for the MPDSS was achieved with the combination of reflectors and the Peltier device, attaining a thermal efficiency of 53.96 % and a 148 % improvement in distillate yield. Also, the thermal efficiency of PDSS, MPDSS, MPDSS-R, MPDSS-C, MPDSS-NTSM, and MPDSS-P was 35.46 %, 42.23 %, 46.77 %, 50.89 %, 48.33 %, and 54.67 %, respectively. While the exergy efficiencies ranged from 3.44 % for the PDSS configuration to 4.87 % for the MPDSS-P configuration. Interestingly, the MPDSS-C configuration achieved an exergy efficiency of 4.64 %. The emissions for MPDSS, MPDSS-R, MPDSS-C, MPDSS-NTSM, and MPDSS-P are estimated at 15.03, 14.62, 14.09, 14.30, and 13.79 tons a year, severally. The enviroeconomic parameters were 218, 212, 204, 207, and 200 a year for MPDSS, MPDSS-R, MPDSS-C, MPDSS-NTSM, and MPDSS-P, respectively. Finally, the water expenses are as follows: $0.343/L for the PDSS, $0.292/L for the MPDSS, $0.220/L for the MPDSS-R, $0.082/L for MPDSS-P, $0.105/L for the MPDSS-C, and $0.114/L for the MPDSS-NTSM.

The pyrolytic distillation of waste lubricants with waste oilfield scale into value-added fuel

The ever-increasing generation of waste materials has become a major environmental concern, highlighting the need for sustainable waste management strategies. This study explores the catalytic pyrolysis of waste lubricant oils using a waste oilfield scale as a low-cost solid catalyst to produce value-added fuel products. The pyrolytic distillation of waste engine oil was carried out in a manual distillation unit, employing a calcium carbonate (CaCO3) scale as a catalyst under various reaction conditions. Distillation experiments were conducted at 300 °C, 320 °C, and 350 °C, with and without adding NaOH and CaCO3 catalysts. The distillate fractions were characterized, and their properties were compared to standard fuel specifications. The results demonstrated that increasing the pyrolysis temperature and employing CaCO3 as a catalyst significantly enhanced the distillate yield and improved key fuel properties. At 350 °C, the distillate yield reached 56 % with 4 g of CaCO3, exhibiting desirable density (0.8049 g/cm3), viscosity (2.31 cSt at 40 °C), sulfur content (0.43 wt%), and a calorific value of 43,152 kJ/kg. Further, the distillate fractions were separated into gasoline (80–150 °C), kerosene (180–270 °C), and gas oil/diesel (270–350 °C) ranges, with the diesel fraction showing a promising cetane number of 51. The catalytic pyrolysis fuel (CPF) obtained from distillation with 4 g CaCO3 at 350 °C, followed by bleaching with CaO, exhibited excellent properties, including a density of 0.8297 g/cm3, viscosity of 2.71 cSt at 40 °C, pour point of −12 °C, sulfur content of 0.201 wt%, and a calorific value of 43,961 kJ/kg. The GC analysis revealed a paraffin-rich composition in the desired fuel ranges, contributing to the desirable fuel properties.

Effects of the depth of hydro desulfurization of raw materials on the yields of catalytic cracking products

The article is devoted to the problem of complex processing of oil feedstock and increasing the output of light petroleum products, in particular, catalytic cracking gasoline. Currently, the oil refining industry of Kazakhstan is faced with the task of complex processing of hydrocarbon raw materials, increasing the depth of processing and output of light petroleum products. In this connection it is urgent to solve the problem of lack of raw materials for oil refineries of the Republic of Kazakhstan. The complexity of solving the problem of processing residues of oils, fuel oil and intermediates of secondary processes lies in the fact that they contain a large amount of various sulfur compounds. This problem concerns not only domestic refineries, for example, oil from Uzbekistan fields contains a relatively large amount of SO2 compounds, which in turn contains about 1.28% sulphur. The high content of sulfur compounds in oil not only negatively affects the quality and environmental friendliness of manufactured products, but also reduces the service life of equipment and oil refineries. In this regard, the preparation and hydrodesulfurization of raw materials is one of the main issues of intensifying the process of catalytic cracking of petroleum raw materials of "PKOP" LLP. The issues of possibility of modernisation of catalytic cracking process units by including the process of hydrodesulphurisation of feedstock in order to improve the quality and yield of light products when using fuel oil and secondary intermediates having a large volume of various sulphur compounds in their composition have been considered by the authors. To evaluate the influence of the depth of hydrodesulfurisation of feedstock on the yields and composition of catalytic cracking products, the cracking of crude and hydrotreated hydrogenated vacuum gas oil mixed with fuel oil was carried out on a laboratory unit. The experiments were carried out on a fluidised catalyst bed at mass feed rates of 2h-1 and 4h-1, catalyst to feed ratio of 3:1 and temperature equal to 5100 C. The analysis of the experimental data obtained showed that preliminary hydrotreating of a mixture of vacuum gas oil and sulfur fuel oil followed by catalytic cracking increases the depth of oil refining and helps to increase the yield of catalytic distillate, improves its quality, which ultimately leads to a decrease in environmental pollution with sulfur compounds.

Enhanced water production in pyramid solar stills: Utilizing suspended trays, fogging system, and forced condensation

This work investigated how to improve the thermal efficiency of pyramid distiller (PSD). A modified PSD (MPSD) was constructed with suspended trays (4-cm width) on three vertical walls. The performance of the MPSD with and without a fogging system was evaluated. Additionally, the MPSD was integrated with an external condensation unit using a withdrawing fan operating at various speeds (1, 1.5, 2, 2.5, 3, & 3.5 rpm). The MPSD with suspended trays exhibited a significant improvement, achieving a 35 % increase in distillate yield compared to the PSD. The MPSD with a fogging system demonstrated a 160 % yield increase. The highest thermal performance for the MPSD with trays, fogger, and external condenser was attained at a fan speed of 2 rpm. At this setting, the MPSD's productivity increased by 194 % with a thermal efficiency of 62.4 %. Notably, the cost of water production decreased from 0.24$/L for the PSD to 0.18$/L for the MPSD. These findings suggest that the MPSD with suspended trays, fogging system, and external condenser offers a promising approach to enhance both the yield and efficiency of solar desalination.

Impact of lanthanum ion exchange and steaming dealumination on middle distillate production using nanosized Y zeolite catalysts in hydrocracking reactions.

In the field of hydrocracking reactions, achieving optimal middle distillate yields remains a persistent challenge with commercially available zeolite Y catalysts. This limitation is attributed to challenges related to diffusion constraints within the catalyst. In response, we present a promising solution not only to these problems but also to the challenges encountered in nanosized Y zeolites when attempting to generate acidic sites within their structure and when analyzing their performance in vacuum gas oil hydrocracking. NiMo catalysts based on nanosized Y zeolites with different crystal sizes exchanged with lanthanum, effectively address diffusion issues and significantly enhance catalyst performance compared to dealuminated nanosized and commercial Y zeolite under the same reaction conditions. The catalysts were characterized by TGA, ICP-OES, XPS, N2 physisorption, FT-IR for pyridine acidity, TEM-mapping, and the 3-methyl thiophene reaction to test the hydrogenating capacity. Surface analysis and microscopy showed greater porosity in the catalysts with smaller zeolites and different arrangements of their components. The catalysts based on steamed protonated nanosized Y zeolites with a larger size and lanthanide nanosized Y zeolite with a smaller size yielded more middle distillates. Research provides a comprehensive analysis, providing a correlation between the catalytic performance and the size of the nanosized Y zeolite.

A performance neural network model for conventional solar stills via transfer learning

Predictive solar-desalination models are becoming more widespread using ML and AI. However, forecasting solar still water productivity based on numerous designs still needs to be improved. Herein, we used transfer learning to create precise supervised predictive ANN regression models for water productivity (L/m2.day) predictions based on literature findings. Such observation datasets from single-basin solar stills were utilized to build the random initialization ANN model. The transfer learning method was applied to the latter model by taking the learned network (weights) for fine-tuning the hyperparameters from the earlier developed novel hybrid solar still known as the source (pre-trained) ANN model, to predict the target ANN model. Based on most minor statistical errors, the pre-trained model with 5–64–64-1 architecture and ReLU activation function was the most appropriate for water productivity prediction. All created ANN models were compared to the MLR model. The results revealed that the generated target ANN model outperformed the ANN RI and MLR with OI values of 0.872, 0.834, and 0.803, respectively, in all modeling stages. The target ANN model's accuracy and generalization were sufficient. The target ANN model had residuals of forecasted distillate values of around 1%. This work discusses the significance of transfer learning to generate accurate target ANN models for predicting freshwater outputs in single-slope solar stills, which can be integrated with established theoretically tuned parameters to enhance performance and maximize distillate water yields.

Optimizing water resources for sustainable desalination: The integration of expert systems and solar energy in experimental applications

The integration of renewable energy sources with multi-energy systems present challenges and opportunities to enhance sustainability. Among these, solar stills have emerged as a solution for water desalination. With the advent of expert system technologies, avenues are opened for improving the operational efficiency of solar distillers. This paper presents an innovative approach utilizing correlation analysis, ReliefF for feature selection, and a k-Nearest Neighbor (kNN) algorithm for forecasting the cumulative distillate output of a double slope solar still. The analysis is based on a 6-cases-based dataset, which includes variations in distillate output relative to different operational-environmental conditions. Key features that significantly impact overall performance were identified to manage the solar distiller productivity. The findings reveal that the maximum distillate output was 1610 ML/m2.day due to incorporating reflective materials and phase change materials (PCM) in enhancing distillation rates. The kNN model was evaluated based on its R2, RMSE, and CVRMSE, with the best models achieving scores of 0.995, 0.0033, and 0.1666, respectively. These metrics underscore the effectiveness of the proposed machine learning approach in predicting distillate output, thereby enabling informed management of solar distillation processes. Combining renewable energy technologies and computational intelligence holds significant promise for sustainable environmental management, as the study presented.

Enhancing coiled solar still performance with vertical wick distiller, reflectors, nanomaterial-infused PCM, and condenser integration

This study explored methods to enhance the performance of a coiled solar still (COSS). One technique involved adding a vertical wick distiller (VWSS) with built-in reflectors positioned after the COSS. Additionally, the research examined the impact of incorporating a fan and a separate condenser on the COSS's distillate output. Finally, the investigation assessed the potential advantages of incorporating paraffin wax infused with nanomaterial beneath the COSS base. The key findings revealed significant improvements in distillate production with the COSS modifications. Compared to a standard solar still (CSS), the COSS alone demonstrated a 76 % increase in daily output. Integrating a heating coil and internal reflectors with the COSS further boosted productivity by an impressive 92 %. The most significant advancements were achieved by combining the COSS with a VWSS and additional features. The MCOSS (COSS with VWSS and internal reflectors) exhibited a remarkable 209 % increase in distillate production compared to the CSS. This value increased to a staggering 269 % when incorporating a heating coil, VWSS, and an external condenser. Adding a fan to the MCOSS further enhanced efficiency to 68 %. Notably, incorporating nanomaterial-infused paraffin wax (PCM-Ag) with the MCOSS with VWSS resulted in a 246 % increase in productivity compared to the standard design. The research also revealed a significant decrease in freshwater production costs. The cost per liter of freshwater was determined to be $0.024 for the CSS and a considerably lower $0.0126 for the MCOSS with a fan.

Year around study of tubular solar still with green almondshells biowaste as energy storage material: energy, economic, and environmental analysis.

Solar-based desalination is one of the prominent contributors to overcoming the water scarcity problems in desert areas and a major alternative to fossil fuel-based desalination methods. The present study focuses on utilizing green almond shells (green almond shells) as energy storage materials in tubular solar still (TSS) to enhance water productivity, energy efficiency, and economic and environmental analyses. Further, this study discusses the yearly water output, annual energy efficiency, and economic and environmental analyses. Two different TSS were utilized which consists of conventional TSS (CTSS) without any storage materials and modified TSS with the inclusion of green almond shells (MTSS) in the climatic conditions of Chennai, India. The yearly distilled water output from the CTSS and MTSS was evaluated as 512 and 691.2kg/m2, respectively. The yearly distilled water output from the MTSS is 26% higher when compared to the CTSS. Furthermore, the maximum monthly energy efficiency of the CTSS and MTSS was 14.4 and 19.44%, respectively. The annual energy efficiency of the CTSS and MTSS is 12.6 and 17.02%, respectively. The economic analysis of the system is also carried out, and the findings show that better economic feasibility is achieved in MTSS considering the INR 5 (Indian Rupees) cost of water. The payback period for MTSS was 12months, while for CTSS it is calculated to be 20months. Furthermore, CO2 emission and mitigation have also been evaluated, and the results indicate that the utilization of porous material has increased the emission for MTSS, while CO2 mitigation has been significantly higher as compared to the CTSS system.

A case study on single basin solar still augmented with wax filled metallic cylinders

This experimental study introduces a novel approach to enhancing solar still performance through the integration of wax-filled rods, marking a significant advancement in solar desalination technology. These rods, innovatively designed to absorb and store both sensible and latent heat during peak solar radiation hours, release this stored energy gradually, particularly during the evening and night. This unique mechanism results in a notable and consistent increase in water temperature within the modified solar still after 17:00, setting it apart from conventional models. The study's findings reveal that the modified solar still achieves a 12.8 % higher cumulative distillate yield and a 16.3 % increase in efficiency compared to traditional solar stills. Furthermore, this enhancement translates into a 6.3 % reduction in distillate production costs, underscoring the economic viability and superior performance of the modified design.

A new leaf essential oil from the Andean species Gynoxys szyszylowiczii Hieron. of southern Ecuador: chemical and enantioselective analyses

The essential oil obtained from the dry leaves of Gynoxys szyszylowiczii Hieron. was described in this study for the first time. The chemical analysis, conducted on two stationary phases of different polarity, permitted to identify sixty-four compounds, that were quantified with at least one column. The main components, on a non-polar and polar stationary phase respectively, were germacrene D (21.6–19.2%), α-pinene (4.4–4.9%), n-tricosane (4.3% on both columns), (E)-β-caryophyllene (3.3–4.3%), 1-docosene (3.2–2.8%), α-cadinol (2.8–3.1%), and cis-β-guaiene (2.6–3.0%). This investigation was complemented by the enantioselective analysis of some major chiral compounds, carried out on two chiral selectors based on β-cyclodextrines. As a result, (S)-( +)-α-phellandrene, (S)-( +)-β-phellandrene, and (1S,2R,6R,7R,8R)-( +)-α-copaene appeared enantiomerically pure, whereas α-pinene, β-pinene, terpinen-4-ol, and germacrene D were detected as scalemic mixtures. Finally, linalool was practically racemic. The distillation yield, analytically calculated by weight of dry plant material, was 0.03%.