Root‐lesion nematodes of potato: current status of diagnostics, pathogenicity and management

Root‐lesion nematodes of the genus Pratylenchus are migratory endoparasites with worldwide economic impact on several important crops including potato, where certain species like P. penetrans, P. neglectus and P. scribneri reduce the yield and quality of potato tubers. Morphological identification of Pratylenchus spp. is challenging, and recent advancements in molecular techniques provide robust and rapid diagnostics to differentiate species without need of specialist skills. However, the fact that molecular diagnostics are not available for all Pratylenchus species means that there are limitations in worldwide application. In general, root‐lesion nematodes are difficult to manage once introduced into agricultural land and damage can be related to pathogenicity and population densities. In addition, root‐lesion nematodes interact with fungi such as V. dahliae, resulting in disease complexes that enhance the damage inflicted on the potato crop. Management interventions are often focused on limiting nematode reproduction before planting crops and include the application of nematicides, and cultural practices such as crop rotation, cover crops, biofumigation, and biological control. Understanding the limitations of the available crop protection strategies is important and there are many gaps for further study. This review discusses the status of the diagnosis, distribution, pathogenicity and management of the main species of root‐lesion nematodes, reported to infect potatoes worldwide, and highlights areas for potential future research

Solar parabolic dish Stirling engine system design, simulation, and thermal analysis

Modeling and simulation for different parabolic dish Stirling engine designs have been carried out using Matlab®. The effect of solar dish design features and factors such as material of the reflector concentrators, the shape of the reflector concentrators and the receiver, solar radiation at the concentrator, diameter of the parabolic dish concentrator, sizing the aperture area of concentrator, focal Length of the parabolic dish, the focal point diameter, sizing the aperture area of receiver, geometric concentration ratio, and rim angle have been studied. The study provides a theoretical guidance for designing and operating solar parabolic dish Stirling engines system. At Zewail city of Science and Technology, Egypt, for a 10 kW Stirling engine; The maximum solar dish Stirling engine output power estimation is 9707 W at 12:00 PM where the maximum beam solar radiation applied in solar dish concentrator is 990 W/m2 at 12:00 PM. The performance of engine can be improved by increasing the precision of the engine parts and the heat source efficiency. The engine performance could be further increased if a better receiver working fluid is used. We can conclude that where the best time for heating the fluid and fasting the processing, the time required to heat the receiver to reach the minimum temperature for operating the Solar-powered Stirling engine for different heat transfer fluids; this will lead to more economic solar dish systems

Design analysis factors and specifications of solar dish technologies for different systems and applications

In this paper, a feasibility study is carried out in order to investigate the description, working principles of the solar parabolic dish systems worldwide, and their potential use in some countries are given. A study of the system is presented, which able to show the performance of the system and accounting for the main technical aspects of the concentrator, receiver and Stirling engine. The study reviews the parabolic solar dish technologies and the design factors adapted in different applications such as material of the reflector concentrators, shape of the reflector concentrators and the receiver, solar radiation at the concentrator, diameter of the parabolic dish concentrator, sizing the aperture area of concentrator, focal length of the parabolic dish, the focal point diameter, sizing the aperture area of receiver, geometric concentration ratio, and rim angle. In order to identify the optimum design feasible option for installation of the solar dish plants, the technical characteristics of some implemented solar dishes worldwide are presented. The study take into consideration available solar potential and the different designs of solar dishes

Tilt and azimuth angles in solar energy applications – A review

This paper presents a review of tilt angle and azimuth angles in solar energy applications. The paper involves an overview of design parameter, applications, simulations and mathematical techniques covering different usage application. The number of references analysing the tilt angle deployment in the context of the research papers of the different countries currently having operations in solar systems is much more significant. Different kinds of models and test methods of optimum tilt angle in different solar systems have been developed since 1956 which can be distinguished by their particular mathematical models or tracking techniques as shown in the latest researches. The mathematical models allows the calculation of different parameters of the solar radiation, the angle of inclination, and the optimum tilt angle of the collecting surface and the effects acting on the system

Construction of ovine GH-pmKate2N expression vector and its uptake by ovine spermatozoa using different methods

This study aims to produce transgenic ovine spermatozoa bearing Ossimi sheep growth hormone (Os_GH) cDNA using different methods. The complete coding sequence of Os_GH has been registered in GenBank accession no. KP221575. The sequence of Os_GH cDNA has been subcloned into pmkate2-N expression vectors to construct Os_GH-pmKate2-N vector. Five groups of sperm uptake were submitted. All groups were incubated at 37 °C for 1 h: Control (sperm cells were incubated without vector), Traditional incubation (sperm cells were incubated with vector), Heat shock (sperm cells were incubated with vector at 4 °C for 20 min and heated for 2 min at 42 °C), Heat shock + Dimethyl sulfoxide (DMSO) (sperm cells were incubated with vector and supplemented with 3% of DMSO and then submitted to heat shock regime) and DMSO (sperm cells were incubated with vector and supplemented with 3% DMSO). The sperm genomic DNA in groups was extracted. The Os_GH-pmKate2-N vector was introduced efficiently into the head of sperm cells in all treated groups. Adding DMSO either with or without heat shock increased the sperm uptake. The progressive motility was reduced (P < 0.05) by 29.9% in heat shock group compared to the control. Adding DMSO improved (P < 0.05) the total and progressive motilities by 8.2% and 19.8%, respectively in heat shock group compared to the heat shock group without DMSO. The results documented the ability of ovine spermatozoa to uptake the exogenous vector. Also, sperm incubation with 3% DMSO is the best method to introduce the exogenous vector into spermatozoa without notable adverse effects on sperm motilities

Design analysis of solar parabolic trough thermal collectors

This paper presents a review of the design parameters, mathematical techniques and simulations used in the design of parabolic trough solar systems, along with a review on their applications. Recent studies that analyze the deployment of solar parabolic trough collectors (SPTC) in different countries and the operational SPTC plants are also presented and discussed. The paper also discusses the different kinds of software and test methods of solar collectors developed since 1981 which can be distinguished by their particular mathematical models or tracking techniques. In particular, since the mathematical models are especially required for the design, analysis, testing and validation of the systems results as they provide an approximation of the dynamic behavior of the physical properties of the system, they are discussed in depth. The mathematical models allow the calculation of different parameters of the solar parabolic trough system, the angle of inclination of the collecting surface and the forces acting on the system. The validity and experimental validation of the major mathematical models on practical solar parabolic trough concentrators, receivers and other components of different dimension are also reviewed. The paper showed the optical efficiency values are close to 63% and the theoretical peak optical efficiency reached 75%