Commercial Plant Research Articles

On outdoor testing procedures of large samples of PV modules

AbstractSTC power control of PV module supply requires testing large samples of modules with low uncertainty. This paper analyses the feasibility of outdoor measurements with the modules kept at their operating positions. The classical procedure of recording I‐V curves and translating them to STC in accordance with IEC‐60891:2021 using the cell temperature directly observed at a few points of the rear of the module entails expanded uncertainties larger than 3% (k = 2), which is too much for this procedure being accepted in quality controls with contractual consequences. A convenient procedure for overcoming this barrier consists in comparing the I‐V curves of a tested and a reference module of the same type, both working under the same operating conditions. The latter is mostly secured if they are in adjacent positions. However, when the procedure is applied to large samples of PV modules kept in their operating positions, the distance between both modules can reach tens of meters and significant inter‐module temperature differences can arise. A method for counterbalancing these differences consists of correcting the measured power values by considering the temperature difference observed at the back‐sheet centres of the tested and the reference modules. That also provides clues to estimating the uncertainty of the results. This procedure has been applied in seven testing campaigns, carried out at commercial PV plants. Dedicated instrumentation, based on two radio linked I‐V tracers, allowing the simultaneous measurement of the I‐V curves and of the temperature at the centres of the reference and the tested modules, has been developed for that. The resulting uncertainties are similar to those corresponding to high‐quality solar simulators and low enough for dealing, in practice, with strict quality control requirements.

NEMATODES AND ROOT SYSTEM ARE AFFECTED BY RHIZOBACTERIAL CONSORTIUM IN THE THIRD GENERATION OF COMMERCIAL BANANA PLANTS

Rhizobacteria has shown promising results in managing nematodes and improving the root system of banana plants. However, their effects on commercial banana plants in different generations remain unclear. In this study performed under field experiment, we evaluated the effect of three types (injection, edaphic and foliar) of a local rhizobacterial consortium application on the system root, nematode populations, and their damage in the third-generation plants. Only mother and daughter plants were treated twice with the rhizobacteria. Plants not treated with rhizobacteria constituted the control treatment. Our results show that rhizobacteria affect different underground tissues and nematodes in third-generation banana plants. Helicotylenchus spp., Meloidogyne spp., Pratylenchus spp., Radopholus similis, and Rhabditis spp. were the nematodes found in banana roots. R. similis population and the damage in the root system of banana plants were reduced significantly by the rhizobacteria edaphic application. The application of rhizobacteria could be a sustainable management strategy over time to improve the root system and suppress nematodes, and their damage in commercial banana plants.

Primeiro registro de Nipaecoccus nipae (Maskell, 1893) (Hemiptera: Pseudococcidae) em Euterpe precatoria Martius (Arecaceae) no Brasil

Euterpe precatoria Martius, 1824 is a palm tree of great socioeconomic importance for the northern region of Brazil, whose heart of palm and fruits are economically exploited. For the expansion of its cultivation in commercial plantations, there is a need to know the phytosanitary aspects of the crop, especially the associated insect pests. Thus, this work aimed was to record the scale insect Nipaecoccus nipae (Maskell, 1893) (Hemiptera: Pseudococcidae) infesting E. precatoria. Populations of this species were observed on E. precatoria plants in Rio Branco, state of Acre, Brazil. Thus, this is the first record of N. nipae on single açaí palm tree in the state of Acre and Brazil. Due to the socioeconomic importance of this palm for the North region and the damaging potential of N. nipae, further studies are strongly recommended in order to determine the level of damage and control alternatives.

Effects of ammonia co-firing ratios and injection positions in the coal–ammonia co-firing process in a circulating fluidized bed combustion test rig

Ammonia (NH3) co-firing is a promising technology for reducing greenhouse gas emissions in coal-fired power plants. Prior to commercialization, an experimental study on coal–NH3 co-firing in a pilot-scale circulating fluidized bed (CFB) combustion test rig was conducted for technical verification. The comprehensive combustion characteristics, including pollutant emission, combustion efficiency, and ash properties, of NH3 co-firing with sub-bituminous coal in a CFB combustion test rig and the CO2 reduction according to NH3 co-firing ratios under two different injection positions (dense bed zone (DBZ) and wind box (WB) with primary air) were investigated. When NH3 was injected at the DBZ, NO emissions decreased as the NH3 co-firing ratio increased and CO emissions increased more rapidly than with only coal-fired combustion. Compared with only coal-fired combustion, a 25.4% NH3 co-firing ratio at the WB position simultaneously reduced NO and CO concentrations, achieving the highest combustion efficiency without ash-related problems. However, N2O emissions increased by > 1.5 times, indicating the formation of N intermediates during NH3 burning. Therefore, with minor retrofitting, coal–NH3 co-firing at the WB position is a feasible solution for simultaneously reducing CO2, NO, and CO emissions in commercial CFB combustion plants.

UAV-based thermography reveals spatial and temporal variability of evapotranspiration from a tropical rainforest

Evapotranspiration (ET) from tropical forests plays a significant role in regulating the climate system. Forests are diverse ecosystems, encompass heterogeneous site conditions and experience seasonal fluctuations of rainfall. Our objectives were to quantify ET from a tropical rainforest using high-resolution thermal images and a simple modeling framework. In lowland Sumatra, thermal infrared (TIR) images were taken from an uncrewed aerial vehicle (UAV) of upland and riparian sites during both dry and wet seasons. We predicted ET from land surface temperature data retrieved from the TIR images by applying the DATTUTDUT energy balance model. We further compared the ET estimates to ground-based sap flux measurements for selected trees and assessed the plot-level spatial and temporal variability of ET across sites and seasons. Average ET across sites and seasons was 0.48 mm h–1, which is comparable to ET from a nearby commercial oil palm plantation where this method has been validated against eddy covariance measurements. For given trees, a positive correlation was found between UAV-based ET and tree transpiration derived from ground-based sap flux measurements, thereby corroborating the observed spatial patterns. Evapotranspiration at upland sites was 11% higher than at riparian sites across all seasons. The heterogeneity of ET was lower at upland sites than at riparian sites, and increased from the dry season to the wet season. This seasonally enhanced ET variability can be an effect of local site conditions including partial flooding and diverse responses of tree species to moisture conditions. These results improve our understanding of forest-water interactions in tropical forests and can aid the further development of vegetation-atmosphere models. Further, we found that UAV-based thermography using a simple, energy balance modeling scheme is a promising method for ET assessments of natural (forest) ecosystems, notably in data scarce regions of the world.

Dragon fruit farming by-products as an important source of several glycosylated flavonoids

Plants are globally used as an alternative for conventional drugs in treatment of many diseases. A significant proportion of medicinal properties of plants is addressed to antioxidant constituents as flavonoids and phenolic acids. The genus Selenicereus, known as dragon fruit, has about 15 species of epiphytic or hemiepiphytic cactus with hotspots in the tropical region of Mexico. Recently, these plants have been the focus of pharmacological studies due to the antioxidant activity of its fruits. Although many studies have investigated the biological activities of fruits, few studies investigated the chemical constituents and biological activities of cladodes. Despite the little knowledge about cladodes, it has been already observed to have higher antioxidant activities and other biological activities than the fruits. Besides this, cladodes are by-products resulting from the year-round pruning. Another important point about studies involving dragon fruit is that none of them identify the variety that is being used. As it is a commercial plant, it has many varieties created by artificial selection and hybridization such as many other food plants. In this study we found that varieties from the same species showed quantitative and qualitative differences in the metabolite profile using LC-MS. Metabolite profile from Cerrado (Selenicereus setaceus) was closer to Branca (Selenicereus undatus) than Thick King (S. setaceus), as well as Golden (S. undatus) was closer to Thick King than Branca. These results show that it is essential to identify varieties that are being used in the studies, whereas studies that attempt to replicate the experiments or use these plants for phytopreparations are prone to mislead.

Using Transferable Eucalypt Microsatellite Markers to Identify QTL for Resistance to Ceratocystis Wilt Disease in Eucalyptus pellita F. Muel. (Myrtales, Myrtaceae)

The deployment of Eucalyptus pellita trees that are resistant to Ceratocystis manginecans is essential for the commercial plantations and therefore the sustainability of forest industries in Southeast Asia that utilize this resource. Current screening procedures are time-consuming and expensive but could be expedited with the aid of marker-assisted selection and breeding. The identification of genotypes with resistance to the disease may be facilitated if microsatellite markers developed in other Eucalyptus species are transferable and can be linked to quantitative trait loci (QTL) for disease resistance. This possibility was tested in 111 full-sib progenies and their parents by genotyping with 49 microsatellite markers developed in other Eucalyptus species. Disease development was assessed after stem inoculation with C. manginecans isolate Am60C. The disease index (DI) varied from 0 to 20% of stem length. There was a continuous distribution of resistant and susceptible seedlings with 60% in the resistant category. Of the 30 acceptable markers, 17 (56%) defined two linkage groups (LG). In each LG, one QTL with a significant logarithm of odds (LODs > 13) was identified. The transferability of microsatellite markers developed in other Eucalyptus species facilitated the rapid identification of LGs and QTLs in E. pellita. To further refine the linkage map, the testing of more microsatellite markers and a larger population of progenies are required.

Detection of Brasiliomyces malachrae Causing Powdery Mildew on Ornamental Cotton (Gossypium hirsutum) plants in Mexico.

Cotton (Gossypium L.; Malvaceae) is the most important fiber crop worldwide, also as a source of vegetable protein and edible oil. Cultivated species of cotton were apparently domesticated independently in four separate regions, in both the Old and the New World. Due to its economic importance, it is necessary to study the diseases that limit its production. During July of 2020-2022, symptoms of powdery mildew were observed on 80 ornamental cotton plants in a nursery located in Cuautla (18°52'38"N; 98°58'28"W), Morelos, Mexico. Disease incidence was 29%. Signs first appeared as small white colonies, which subsequently developed into abundant mycelial grown mainly on the upper leaf surface. White patches of mycelia were observed on leaves. In advanced stages of the disease, plants exhibited symptoms of yellowing, necrosis, and early defoliation. Microscopic analysis from 10 plant samples showed that mycelia were amphigenous, epiphyllous, in thin patches and evanescent. Hyphae were hyaline, thin walled and hyphal appressoria were simply lobed. Chasmothecia (n=50) were sub-aggregate, generally spherical to subglobose (46-61 µm in diameter), whitish, subhyaline, smooth, with a peridium of a single cell layer and appendages were absent. Three asci per chasmothecia, subspherical, 30-44 × 26-38 µm, with 4-6 ascospores per ascus. Ascospores were hyaline, ellipsoid to ovoid (16-23 × 10-18 µm). The asexual phase was not observed. The characteristics observed correspond to Brasiliomyces malachrae (Braun and Cook 2012; Cabrera et al. 2018). A voucher specimen was deposited in the Herbarium of the Department of Plant-Insect Interactions at the Biotic Products Development Center of the National Polytechnic Institute under accession no. IPN 10.0114. To confirm identification, DNA was recovered from the fungus and the internal transcribed spacer (ITS) from one sample was amplified by PCR, using the primers ITS1/ITS4 (White et al. 1990). The sequence was deposited in GenBank (OQ546720) and showed 100% sequence homology (647/1642bp) with the type sequence of B. malachrae (LC191217) from Malvastrum coromandelianum in Argentina (Cabrera et al. 2018). Pathogenicity was verified through inoculation by gently dusting conidia from infected leaves onto leaves of five healthy cotton plants. Five noninoculated plants served as controls. All plants were maintained in a greenhouse at temperatures from 28±2°C and relative humidity ranging from 80±5%. The experiment was performed twice. Inoculated plants developed powdery mildew symptoms after 14 days, whereas the control plants remained healthy. The fungus on the inoculated leaves was morphologically identical to that originally observed on diseased plants, thus fulfilling Koch's postulates. To our knowledge, this is the first report of Brasiliomyces malachrae causing powdery mildew on Gossypium hirsutum in Mexico and North America (Farr and Rossman 2023). Powdery mildew on G. hirsutum caused by B. malachrae has been previously identified in Venezuela by Hanlin and Tortolero (1984). This disease could be a primary source of inoculum of powdery mildew for commercial cotton plantations, derived from the free movement of ornamental plants.

Thermodynamic analysis of a gas turbine utilizing ternary CH4/H2/NH3 fuel blends

Ammonia and hydrogen have gained significant interest as fuels for power generation as part of a larger strategy to decarbonization the power generation sector. By mixing these carbon-neutral fuels with natural gas, lower carbon dioxide emissions can be achieved in gas turbine operations without any retrofitting. However, no studies have explored methane-hydrogen-ammonia ternary fuel blends on gas turbines performance and emissions. In this work, a 50 MW simple Brayton cycle model was developed, incorporating operating conditions found in commercial power plants and chemical equilibrium to represent realistic exhaust temperatures and species. Over 5150 fuel combinations of ammonia-hydrogen-methane were assessed and performance parameters (i.e., system efficiency and specific fuel consumption) are reported. The optimal system efficiency changes with fuel composition, with most ternary fuel blends achieving highest system efficiency at equivalence ratios between 0.37 and 0.39. Gas turbines operating with high ammonia concentrate fuel blends achieve high system efficiencies (up to ∼44.6%) but result in high specific fuel consumption (up to 0.44 kg.kWh−1). The fuel blend of 78%/22% H2/NH3 was found to be the optimal fuel choice, achieving higher system efficiency with similar fuel consumption as pure methane.

Development of a novel solar PV module model for reliable power prediction under real outdoor conditions

Accurately predicting and validating the power output of commercial solar PV power plants, remains an important research topic despite numerous studies already conducted. The precision and reliability of power prediction depends on the accuracy of the solar cell parameter values used in the model. A novel analytical technique has been developed in this study for PV power prediction, which employs one and two diode models with 3, 5, and 7 parameters. This new model only requires the manufacturer sheet data and has been validated through indoor and outdoor experiments. The performance of an experimental PV system is evaluated using the proposed solar cell models under varying irradiance and temperature levels. Additionally, the predicted output solar power was experimentally validated under real outdoor conditions in India with higher accuracy. The 7-parameter solar cell model is found to be the most accurate with the least RMSE of 0.02, followed by the 5 and 3-parameter models with RMSEs of 0.04 and 0.07, respectively. Compared to previous methods, the present new model predicts PV power with higher accuracy and lower percentage error. Finally, the study also identifies follow-up photovoltaic research areas.

Trained sensory descriptors and volatile aroma compounds of USDA Select steaks using five grill temperatures

Thirty-three USDA Select boneless top loins were selected from carcasses at a commercial major packing plant, vacuum-packaged, and aged for 14 d (4 °C). The loins were then divided into 10 portions (5 grill temperatures for each of trained sensory panel and Warner-Bratzler shear force). Flat-top electric grills were pre-heated to 1 of 5 different temperatures: 149 °C (149), 177 °C (177), 204 °C (204), 232 °C (232), or 260 °C (260). Steaks were placed on the grill, turned when the internal temperature reached 35 °C and removed when the internal temperature reached 71 °C. A trained sensory panel evaluated ten basic flavors and five texture attributes. Extra cubes from each sample were frozen in liquid nitrogen and stored at −80 °C for GC/MS volatile aroma compound analysis. Beef identity, brown, and roasted flavor descriptors increased linearly (P < 0.001) while bloody/serumy tended to decrease (P = 0.016) and sour flavor decreased (P = 0.006) linearly as grill temperature increased. Furthermore, burnt (deviation P = 0.008) and bitter (deviation P = 0.012) flavor descriptors were affected by effects other than linear or quadratic, while umami (P = 0.002) and overall sweet (P = 0.016) flavors increased quadratically from 149 to 232 then declined at 260 grill temperatures. Two alcohols, eight aldehydes, four alkanes, three furans, eight ketones, and twelve pyrazines were impacted by differences the grill temperature. Increasing grill temperature increases volatile compounds, primarily from the Maillard reaction, that improve positive beef flavor descriptors.

Association of Tomato Chlorosis Virus Complicates the Management of Tomato Yellow Leaf Curl Virus in Cultivated Tomato (Solanum lycopersicum) in the Southern United States

Tomato (Solanum lycopersicum L.) production in the USA has been severely impacted by the tomato yellow leaf curl virus (TYLCV). Furthermore, a complex association of whitefly-transmitted TYLCV (genus, begomovirus) and tomato chlorosis virus (ToCV, genus, crinivirus) were recently identified in tomato. Several tomato cultivars were developed and commercialized with intermediate resistance (IR) against TYLCV-IL (Israel), the predominant strain of TYLCV found in Georgia, USA. TYLCV-resistant cultivars were tested in open field conditions against multiple whitefly-transmitted viruses in Georgia under natural disease pressure during the fall of 2022. The area under disease progress curve (AUDPC) over time showed a steady increase in disease severity among all cultivars. Further analysis of infected samples using high throughput sequencing (HTS) and quantitative PCR (qPCR) revealed the presence of TYLCV and ToCV in symptomatic upper and lower leaves, respectively. Moreover, the presence of both viruses in upper and lower leaves was determined. A mixed infection of both viruses, TYLCV and ToCV, resulted in severe disease development which may enhance the commercial tomato plants to break resistance and lead to decreased fruit quality and marketable yields.

Wind regimes above and below a dense oil palm canopy: Detection of decoupling and its implications on CO2 flux estimates

In tall vegetation canopies, calm weather conditions may result in the formation of an isolated below-canopy air layer. Especially during night, below-canopy carbon dioxide (CO2) fluxes may be concealed from above-canopy eddy covariance (EC) measurements, masking the magnitude of CO2 net ecosystem exchange (NEE). Particular attention to this “nighttime problem” needs to be paid in oil palm (Elaeis guineensis Jacq.) plantations, which can form a dense top canopy and which are grown in tropical regions where wind speeds are often low. Here, we investigated EC-based NEE measurements, wind and micrometeorological patterns, and LiDAR-derived terrain and canopy structure in a mature commercial oil palm plantation in the tropical lowlands of Jambi province, Sumatra, Indonesia. Over 3 years, we assessed the strength of turbulent and thermal mixing and tested five different methods to determine decoupling: (i) single-level (above-canopy) and (ii) two-level (above- and below-canopy) friction velocity (u*), (iii) above- and below-canopy standard deviation of the vertical wind (σw), (iv) bulk Richardson number (Rib), and (v) vertical turbulence intensity (ITurb). Our results show that decoupling is a common phenomenon in this plantation, with the two-level filters of σw and u* being most sensitive in its determination, showing ∼93% nocturnal decoupling. Decoupling is driven by the oil palm canopy structure, which develops a marked blocking layer at ∼10 m above the ground, high frequency of calm weather conditions, inverse temperature gradients and a terrain slope of 3° which was enough to create a thermally-induced drainage flow. Filtering NEE data, especially the two-level filters of σw and u*, challenged estimations of the plantation's CO2 balance due to high uncertainties in nocturnal respiration rates which could not be reduced by adding storage components to the measured fluxes highlighting the importance of additional below-canopy CO2 flux measurements, especially in such a weak-wind and dense-canopy tropical environment.

Pesticides as a potential independent childhood leukemia risk factor and as a potential confounder for electromagnetic fields exposure

BackgroundBoth pesticides and high magnetic fields are suspected to be childhood leukemia risk factors. Pesticides are utilized at commercial plant nurseries, which sometimes occupy the areas underneath high-voltage powerlines. ObjectivesTo evaluate whether potential pesticide exposures (intended use, chemical class, active ingredient) utilized at plant nurseries act as an independent childhood leukemia risk factor or as a confounder for proximity to, or magnetic fields exposure from, high-voltage powerlines. MethodsWe conducted a state-wide records-based case-control study for California with 5788 childhood leukemia cases and 5788 controls that examined specific pesticide use, magnetic field exposures and distances to both powerlines and plant nurseries. Exposure assessment incorporated geographic information systems, aerial satellite images, and other historical information. ResultsChildhood leukemia risk was potentially elevated for several active pesticide ingredients: permethrin (odds ratio (OR) 1.49, 95% confidence interval (CI) (0.83–2.67), chlorpyrifos (OR 1.29, 95% CI 0.89–1.87), dimethoate (OR 1.79, 95% CI 0.85–3.76), mancozeb (OR 1.41, 95% CI 0.85–2.33), oxyfluorfen (OR 1.41, 95% CI 0.75–2.66), oryzalin (OR 1.60, 95% CI 0.97–2.63), and pendimethalin (OR 1.82, 95% CI 0.81–2.25). Rodenticide (OR 1.42, 95% CI 0.78–2.56) and molluscicide (OR 1.22, 95% CI 0.82–1.81) exposure also presented potentially elevated childhood leukemia risks. Childhood leukemia associations with calculated fields or powerline proximity did not materially change after adjusting for pesticide exposure. Childhood leukemia risks with powerline proximity remained similar when pesticide exposures were excluded. DiscussionPesticide exposure may be an independent childhood leukemia risk factor. Childhood leukemia risks for powerline proximity and magnetic fields exposure were not explained by pesticide exposure.

Toxicity of Bacillus sp. (Bacillales: Bacillaceae) on the fungus gnats, Bradysia aff. ocellaris larvae (Diptera: Sciaridae)

Bacillus thuringiensis (Bt) Berliner has potential for use in insect management. Its use can be an alternative for the management of Bradysia aff. ocellaris (Comstock), considered one of the main strawberry pests in a soilless system. Therefore, the objective of this work was to evaluate the toxicity of different bacteria on B. aff. ocellaris in laboratory and greenhouse bioassays. The following isolates were used in the experiments: Bacillus circulans (Bc), B. thuringiensis var. oswaldo cruzi (Bto) or B. thuringiensis var. israelensis (Bti) and B. thuringiensis var. kurstaki (Btk) In the laboratory, B. aff. ocellaris larvae showed high susceptibility to Bti isolate (92 % mortality) 14 days after treatment exposure (DAET). In contrast, the isolates Bc, Bto, and Btk showed less than 32 % mortality, not differing from the control treatment (water – 22 % mortality). According to the concentration-response curves the values of lethal concentration LC50 and LC90 were 4 x 106 CFU.mL-1 and 4 x 1015 CFU.mL-1. By applying Bti (4 × 1012 CFU.mL-1) at the base of strawberry plants growing in plastic pots containing commercial plant substrate, a reduction of 26 % in the emergence of B. aff. ocellaris was observed. According to these results, the Bti isolate is considered promising for the formulation of bioinsecticides based on Bt for the management of B. aff. ocellaris in strawberry culture.

Characterisation of Chrysoporthe cubensis and Chrysoporthe deuterocubensis, the Stem Canker Diseases of Eucalyptus spp. in a Forest Plantation in Malaysia

Commercial plantations of Eucalyptus species have been established in Malaysia, especially during the past 10 years, with the aim of sustaining the supply of wood and timber products for industrial use in Malaysia. As part of an assessment of fungal diseases affecting Eucalyptus species in four regions in Malaysia, including Kelantan, Pahang, Sabah, and Selangor, stem canker disease was discovered to be a widespread disease infecting Eucalyptus species in Malaysia. This study aimed to identify the fungus-causing stem canker disease, test its pathogenicity in Eucalyptus, and determine the mating type of isolates from the infected trees. The fungi were identified based on morphology and through comparisons of DNA sequence data from the ITS, β-tubulin 2 gene, and TEF-1α gene regions. Phylogenetic analyses showed that the causal agent of the stem canker was Chrysoporthe cubensis infecting Eucalyptus plantations in Pahang and Chrysoporthe deuterocubensis infecting Eucalyptus plantations in Kelantan, Sabah, and Selangor. We believe this is the first report of Chrysoporthe cubensis-infected Eucalyptus in Malaysia and Southeast Asia, while Chrysoporthe deuterocubensis is the first-reported species infecting Eucalyptus pellita in Malaysia. Moreover, the fact that the mating-type MAT1-1 and MAT1-2 genes and the pheromone genes ppg1, ppg2, pre1, and pre2 were identified in all isolates indicates that Chrysoporthe cubensis and Chrysoporthe deuterocubensis are homothallic mating systems. Pathogenicity was tested on a 3-year-old standing tree, 1-year-old seedling, and detached healthy leaves, which were re-isolated for fulfilling Koch’s postulates. In pathogenicity trials, both Chrysoporthe cubensis and Chrysoporthe deuterocubensis gave rise to lesions on wounded Eucalyptus. Both Chrysoporthe spp. were equally pathogenic to Eucalyptus urograndis and Eucalyptus pellita and should be regarded as a biosecurity concern in Malaysia’s forest plantation industry.

Advanced monitoring of geothermal Organic Rankine Cycles

Geothermal Organic Rankine Cycle (ORC) power plants have tremendous worldwide potential for the utilization of low- and medium-temperature geothermal resources. However, monitoring of such a system is associated with special challenges for plant operators since the generated electrical power fluctuates strongly, which is caused by mainly two reasons: Firstly, due to the changing condensation conditions caused by air-cooled condensers, and secondly, due to the formation of scaling and fouling. Therefore, the process parameters of a geothermal ORC plant are highly variable, both in terms of diurnal and seasonal fluctuations. Considering the currently applied control software in commercial ORC plants, these fluctuations result in challenges regarding a reliable identification of potential degradation processes within the ORC process.This paper presents a novel analytical and data-based methodology for advanced monitoring of the main components of a two-staged subcritical geothermal ORC system in Southern Germany. These components are the heat exchanger, turbine and air-cooled condenser. For this purpose, operational data from more than three years were preprocessed and evaluated.For the shell-and-tube evaporator, this work applies an equation-based simulation model for the calculation of the thermal resistance due to scaling and fouling. For the turbine and condenser, polynomial functions of various degrees and different objective functions for the numerical computation of regression coefficients are examined. Regression models for three years of operation of the investigated geothermal plant were computed and compared with each other.The results indicate that there are no significant negative changes in the operational performance of most ORC main components during the investigated time period. However, negative operational changes are detected over a three-year period for one turbine of the ORC system. The detailed evaluation of the turbine data reveal a decrease of the normalized isentropic efficiency by 10%, which is significantly higher than the calculated RMSE of the developed correlations, thus indicating a clear performance reduction of the turbine. The developed advanced monitoring methodology allows the operator detailed and accurate assessment of the ORC components conditions, which can not be provided by the software solutions of the commercial ORC manufacturer. Furthermore, the presented methodology can also be applied to other thermal cycle systems with similar components, such as the Kalina Cycle.Finally, a user-friendly software application, developed with the MATLAB® App Designer, is presented. The developed software tool facilitates operators to easily and precisely monitor the operation of the main components of a geothermal ORC plant.

Diversity of transgenes in sustainable management of insect pests.

Insecticidal transgenes, when incorporated and expressed in plants, confer resistance against insects by producing several products having insecticidal properties. Protease inhibitors, lectins, amylase inhibitors, and chitinase genes are associated with the natural defenses developed by plants to counter insect attacks. Several toxin genes are also derived from spiders and scorpions for protection against insects. Bacillus thuringiensis Berliner is a microbial source of insecticidal toxins. Several methods have facilitated the large-scale production of transgenic plants. Bt-derived cry, cyt, vip, and sip genes, plant-derived genes such as lectins, protease inhibitors, and alpha-amylase inhibitors, insect cell wall-degrading enzymes like chitinase and some proteins like arcelins, plant defensins, and ribosome-inactivating proteins have been successfully utilized to impart resistance to insects. Besides, transgenic plants expressing double-stranded RNA have been developed with enhanced resistance. However, the long-term effects of transgenes on insect resistance, the environment, and human health must be thoroughly investigated before they are made available for commercial planting. In this chapter, the present status, prospects, and future scope of transgenes for insect pest management have been summarized and discussed.

Determination of optimal soil pH and nutrient concentrations for cultivated rooibos tea using the boundary line approach

Optimal soil pH and nutrient conditions for rooibos cultivation in South Africa have not yet been established as limited field research has been conducted. Soil chemical (0–300 mm) and yield data were collected from 120 commercial rooibos plantations in the main (170 km wide) production region in the Western and Northern Cape Provinces. The optimum and 90%-yield sufficiency soil ranges were determined using the boundary line approach and quadratic regression. The optimum (sufficiency range) soil chemical properties were a pH (KCl) of 4.5 (4.2–4.7), electrical conductivity of 0.23 mS m−1 (0.16–0.30 mS m−1) and acid saturation of 27.5% (17.1–37.8%). The optimum (sufficiency range) soil available macro- and micronutrients (in mg kg−1) were: 16.9 (7.4–26.4) for P, 20.8 (11.5–30.0) for K, 140.3 (95.9–184.7) for Ca, 50.0 (32.3–63.7) for Mg, 8.3 (4.9–11.7) for S, 34.6 (17.2–52.1) for Fe, 5.5 (2.2–8.8) for Mn, 0.30 (0.16–0.45) for Zn, 0.11 (0.07–0.15) for Cu and 0.11 (0.06–0.16) for B. The resultant optimal values for soil pH and available P, K and Mg corresponded with previous published reports on cultivated fynbos species, while published values were not available for the other parameters. The findings of this study are important for sustainable soil fertility management in commercial rooibos tea production in South Africa.

Structure and physical stability of plant-based food gel systems: Impact of protein (mung bean, pea, potato, soybean) and fat (coconut, sunflower)

Despite their popularity, plant-based food gel systems (GS) sometimes have suboptimal texture compared to animal-based products. Therefore, 4 commercial plant proteins (from mung bean, pea, potato and soybean) and 2 commercial plant fats (sunflower oil and coconut fat) in 2 contents (7.5 wt% and 17.5 wt%) were evaluated towards their contribution to structure and physical stability a lean (LGS, no fat) and an emulsified GS (EGS). Generally, protein source had a larger effect on structure and physical stability than fat source and content. Unheated, GS with soybean protein showed most structure and highest physical stability. Heated till 94 °C, the structure of GS increased drastically, but EGS showed less structure than LGS, attributed to low solid fat contents (SFC), hence low rigidity, of the incorporated oil droplets at 94 °C. Cooled till 5 °C all GS showed an additional increase in structure, for GS with mung bean and pea protein accompanied with an increase in physical stability. Overall, EGS with sunflower oil showed less structure and lower stability than EGS with coconut fat, likely due to their different SFC. At 5 °C, Peak force of GS with potato protein was highest. Across protein sources, EGS displayed a higher Peak force with coconut fat than with sunflower oil, again likely due to different SFC, hence, rigidity of the oil droplets. Physical stability of GS did not vary significantly between protein sources, fat sources nor fat contents, after a freeze-thaw cycle, nor during prolonged cold storage.