Optical analytical methods for detection of pesticides

The global pesticide market has grown steadily since the 1940s, with the agricultural sector being the largest user of pesticides. The effect of pesticides on human health is manifested either through direct exposure to the material or indirect exposure to contaminated resources. Farmers and those dwelling near areas where pesticides are used may suffer from direct exposure, while the general population might be exposed indirectly, for example, by drinking contaminated water. Exposure to pesticides may cause a variety of symptoms, including headaches, dizziness, and vomiting, damage the nervous system, and even cause death. The risks involved in pesticide use include air pollution and soil and water contamination. The environmental implications of pesticide use include development of resistance among pests, a decline in biodiversity, interruption of the food chain, and disruption of the ecological balance. Pesticide use may also cause changes in physical parameters of the ecosystem. Effective activity of pesticides requires reaching proper leaf coverage. To prevent pest attacks due to insufficient leaf coverage, farmers tend to apply pesticides in excess. In view of the environmental and health implications of pesticide use, there is a clear need to limit pesticide application. Yet farmers lack the means to perform real-time in situ assessment of leaf coverage. Existing pesticide detection methods are complex, time-consuming, and unsuited to field application. Optical methods have the potential to provide quick assessments and can be used in situ. Several optical methods for detection of pesticides in general and on leaves in particular were developed. The findings indicated that the main problems in pesticide detection using fluorescence are the low autofluorescence of the pesticides and the nonreproducible spectral response of the leaves. These obstacles were solved by employing labeling agents. For example, rhodamine was suggested, mainly due to its excellent surface adhesion and its extremely high fluorescence quantum yield. The labeling agents were sprayed on leaves in the form of aerosols, thus creating a uniform layer of nanocrystals and microcrystals on the surface of the leaves. The effects of pesticides on the spectral characteristics of the labeling agents were examined using laser-induced fluorescence (LIF) spectroscopy. When pesticide droplets were applied to a pretreated leaf, two phenomena were observed. The first was a substantial fluorescence increase. The second was material-specific spectral shifting as a result of interaction between the labeling molecules and organic components in the pesticide droplet. It was possible to utilize these spectral shifts for quantification of the pesticide concentration in the droplet. These spectral shifts enabled detection of pesticides on plants, although they were not sufficient for providing quantitative information on the extent of pesticide coverage. To detect pesticide coverage, several imaging data techniques were applied, such as LIF scanning of the examined plant surface. This method revealed the droplet shape by scanning and recording the fluorescence intensity at many points on a grid. Since application of this method is expensive and time-consuming, a second technique was also developed: it requires only a UV source and a CCD camera and it enables direct imaging of the pesticides on plants. The data obtained included the droplet shape and its location on the plant. When pesticide identification was required, application of a special hyperspectral fluorescence imaging method was introduced. Fourier transform hyperspectral imaging analysis provided simultaneous full spectral resolution at each pixel, enabling identification of the pesticide and its mapping on the plant. In practice, test plants have to be pretreated with labeling material before pesticide application. The changes in the labeling compound fluorescence can then be used for detection of the pesticide on the plant and quantification of the overall coverage. Low-cost mapping of the pesticide microdroplets could be obtained using a CCD camera, while accurate information could be based on Fourier transform hyperspectral imaging. Since these methods provide immediate results, they may allow the farmer to estimate leaf coverage during pesticide application and adjust spraying accordingly. © 2011 by Walter de Gruyter Berlin Boston

The obstacles preventing the small firms in Iraq to export

Export performance is usually taken as one of the important factors in driving a country’s economic growth. Exports can improve the firm’s production efficiency, overcome higher trade barriers and address different market preferences in the competitive international markets. This study investigates the obstacles faced by the small Iraqi firms to export. Four obstacles are considered from a theoretical perspective, as variables that have affected the success of these firms to export, which are (i) the infrastructure, (ii) trade policies, (iii) corruption, crime and security and (iv) finance. The empirical research was conducted through a questionnaire distribution concerned with the textile and food industry sectors in Iraq. Both textile and food industry sectors are of high export potential, but are found to be struggling with international recognition. The impediments or barriers and also the incentives were labelled as the core factors. The results of data analysis obtained from data collected from respondents show that both food and textile sectors have produced similar outputs where their answers are nearly same. Both sectors face the same issues and problems in suggesting the way forward. The small firms in both sectors, with very different products and strategic advantages, require entrepreneurial leadership, strategy and innovation to take advantage of the changing international regulations, favourable domestic factor condition and government support to compete successfully in the international markets

Theoretical Study of the Effect of the Diffusion Length of Electron on the Efficiency of the Single Crystal Silicon Solar Cell

يتضمن البحث دراسة نظرية لتأثير أطوال انتشار مختلفة للإلكترون على معلمات خلية شمسية سليكونية أحادية البلورة.           استعملت قيم مختلفة لطول الانتشار للإلكترون وبواسطة استعمال برنامج الحاسبة الالكترونية بلغة فيجال بيسك. النتائج توضح تزايد معلمات خلية شمسية سليكونية أحادية البلورة مع تزايد طول الانتشار للإلكترون وبالتالي حساب الكفاءة النظرية للخلية والتي تراوحت بين (13.352 - 30.076) %.           وقد تم رسم العلاقة بين  قيم طول الانتشار للإلكترون والمعاملات الداخلة في حساب كفاءة الخلية ومن ثم رسم العلاقة بين أطوال الانتشار هذه والكفاءة النظرية لهذه الخلية إضافة ًإلى ملاحظة تأثير العوامل الأخرى على تلك الكفاءة وتم التوصل من ذلك إلى الملاحظات والاستنتاجات المهمة والتي يمكن تلخيصها في ميزتين: أولا ً: تحسين أطوال الانتشار في كل من السطح الأمامي والخلفي سوف يقلل الخسائر بسبب إعادة الاتحاد عند السطح الأمامي والخلفي ويجعل التيارات الضوئية أقرب إلى القيم المثالية. ثانيا ً: استعمال طبقة قاعدة ذات سمك أقل من طول الانتشار للحاملات الأقلية ، والتي تحسن كفاءة التجميع للخلية الشمسيةThis work includes a theoretical study to the effect of different diffusion lengths of electron on the parameters of the single crystal silicon solar cell.              Different values of diffusion length of electron are used and by using electronic calculator programme in visual basic language. The results show increasing the parameters of single crystal silicon solar cell with increasing the diffusion length of electron and consequently calculating the theoretical efficiency of the cell, which varied between (13.352 - 30.076) %.             The relationship between values of the diffusion length of electron and the input parameters in calculating the cell efficiency has been drawing and then drawing the relationship between these diffusion lengths and the theoretical efficiency of this cell as well as noticing effect of other parameters on that efficiency and important notes and conclusions is achieved which can be summarized in two features: Firstly: Improving the diffusion lengths in both the top surface and the back surface would reduce losses due to bulk and surface recombination velocities at the front and back surface and bring measured photocurrents closer to the idealized values.   Secondly: Using a base layer of a thickness smaller than the minority carrier diffusion length, which improve the collection efficiency of the solar cell

Effect of Addition AgNO3 on some Optical Properties of Polystyrene

في هذا البحث تم دراسة تأثير إضافة نترات الفضة على بعض الخواص البصرية للبولي ستايرين. ولهذا الغرض تم تحضير نماذج  بإضافة  AgNO3إلى البولي ستايرين وبنسب حجمية مختلفة من هذه الأملاح مع البوليمر وبسمك مختلف. تم تسجيل طيفي الامتصاص والنفاذية ولمدى الاطوال الموجية nm(1100-190). وحساب معامل الامتصاص و فجوة الطاقة للانتقال غير المباشر المسموح و الممنوع.In the present work, effect of addition AgNO3 on some optical properties of polystyrene has been studied. for that purpose, many samples has been prepared by adding AgNO3 on the polystyrene by different volume percentages from these salts with polymer and by different thickness.The absorption and transmission spectra has been recorded in the wavelength range (190-1100)nm. The absorption coefficient and energy gap of the indirect, allowed, forbidden transition have been determined. &nbsp

EPIDEMIC AS METAPHOR: THE ALLEGORICAL SIGNIFICANCE OF EPIDEMIC ACCOUNTS IN LITERATURE

Epidemic as Metaphor: The Allegorical Significance of Epidemic Accounts in Literature. Our paper searches for those common elements in selected literary representations of the plagues that have affected humanity. As a theoretical framework for our research, we have considered the contributions of Peta Michell, who equals pandemic with contagion and sees it as a metaphor; Susan Sontag views illness as a punishment or a sign, the subject of a metaphorization. Christa Jansohn sees the pest as a metaphor for an extreme form of collective calamity. For René Girard, the medical plague is a metaphor for the social plague, and Gilles Deleuze thinks that fabulation is a “health enterprise.” From the vast library of the pandemic, we have selected examples from Antiquity to the 19th century: Thucydides, Lucretius, Boccaccio, Daniel Defoe, Mary Shelley, Edgar Allan Poe, and Jack London. For Camus, the plague is an allegory of evil, oppression and war. Our paper explores the lessons learned from these texts, irrespective of their degree of factuality or fictionality, pointing out how the plague is used metaphorically and allegorically to reveal a more profound truth about different societies and humanity. REZUMAT. Epidemia ca metaforă: semnificaţia alegorică a relatării epidemiilor în literatură. Lucrarea noastră caută acele elemente comune în reprezentări literare selectate ale epidemiilor care au afectat omenirea. Drept cadru teoretic pentru cercetarea noastră, am luat în considerare contribuțiile lui Peta Michell, care echivalează pandemia cu contagiunea și o vede ca pe o metaforă; Susan Sontag consideră boala ca fiind o pedeapsă sau un semn, subiectul unei metaforizări. Christa Jansohn vede epidemia ca metaforă a unei forme extreme de calamitate colectivă. Pentru René Girard, ciuma medicală este o metaforă a ciumei sociale, iar Gilles Deleuze crede că fabulația este o „întreprindere de sănătate”. Din vasta bibliotecă a pandemiei, am selectat exemple din Antichitate până în secolul al XIX-lea: Tucidide, Lucrețiu, Boccaccio, Daniel Defoe, Mary Shelley, Edgar Allan Poe și Jack London. Pentru Camus, ciuma este o alegorie a răului, a asupririi și a războiului. Lucrarea noastră explorează lecțiile învățate din aceste texte, indiferent de gradul de factualitate sau ficționalitate, subliniind modul în care pandemia este utilizată metaforic și alegoric pentru a dezvălui un adevăr mai profund despre diferite societăți și umanitate. Cuvinte-cheie: epidemie, ciumă, Decameronul (Boccaccio), Jurnal din anul ciumei (Daniel Defoe), Regele ciumă (Edgar Allan Poe), Ultimul om (Mary Shelley), Despre natura lucrurilor (Lucretius), Ciuma (Albert Camus), Ciuma stacojie (Jack London), Războiul Peloponesiac (Tucidide

An analysis of third intermediate grade mathematics course book in the light of CFBT standards

The current research aimed to identify the availability of British (CFBT) standards in the mathematics course book for the third intermediate grade by analyzing its content, the research community consisted of the mathematics book in its first and second parts scheduled for third-grade intermediate students for the academic year 2020-2021. As for the research sample, it is the research community, while the research tool consisted of two parts, the first for content standards, and the second for process standards according to the list of standards. The validity of the tool was confirmed by presenting it to experts and referees. As for the reliability of the analysis, It has been calculated by two methods: reliability across others and reliability through time, where it appeared in a high percentage, the researcher relied on it on frequencies and percentages as statistical means in this research, the results showed the following: By analyzing the content of the mathematics book for the third intermediate grade In light of the standards (CFBT), which consists of two parts, the first section:  content standards consists of three fields of arithmetic and algebra   in the first rank with a percentage of (60%), and engineering and measurement in the second rank with a percentage of (29%), and data processing in the last rank by (11%), As for the second section, Operations Standards, it consists of one fields, which is reasoning and solving problems, and it came at a percentage of (13%). In light of the research results, a set of recommendations and proposals have been written, including: Benefiting from the list of CFBT standards in developing a mathematics textbook for the third intermediate grade, and seeking to prepare national standards for curricula in Iraq in general and mathematics curricula in particular

Deducing the digital evaporation loss model of high dam reservoir

Evaporation is the most negative phenomenon, causing huge losses in the water capacities of reservoirs. For example, evaporation at the High Dam (HD) reservoir (the water resources bank of Egypt that supplies Egypt with about 97% of its freshwater needs) which is characterized by its large water surface area (about 6000 km2 at water level 178 A.M.S.L). This reservoir, due its geographical location, is exposed to a range of climatic factors which increase evaporation rate annually, and consequently, increase the total loss of its capacity (about 10 Billion m3 of the HD reservoir capacity is lost annually due to evaporation phenomenon). Many organizations rely on an evaporation chart that gives the value of evaporation loss according to some climate variables. With respect to the problem of malfunctions of some stations, or in case of lack of data for any reason, it is important to have a digital evaporation loss model that gives the missed evaporation loss in the High Dam reservoir directly, according to two factors; the given month and the average monthly water level. This paper will explain how to get benefit from the available data of hydro-meteorological stations distributed within the High Dam reservoir, to predict the digital evaporation loss surface using the GIS prediction and conversion tools

Deducing the digital evaporation loss model of high dam reservoir

Evaporation is the most negative phenomenon, causing huge losses in the water capacities of reservoirs. For example, evaporation at the High Dam (HD) reservoir (the water resources bank of Egypt that supplies Egypt with about 97% of its freshwater needs) which is characterized by its large water surface area (about 6000 km2 at water level 178 A.M.S.L). This reservoir, due its geographical location, is exposed to a range of climatic factors which increase evaporation rate annually, and consequently, increase the total loss of its capacity (about 10 Billion m3 of the HD reservoir capacity is lost annually due to evaporation phenomenon). Many organizations rely on an evaporation chart that gives the value of evaporation loss according to some climate variables. With respect to the problem of  malfunctions of some stations, or in case of lack of data for any reason, it is important to have a digital evaporation loss model that gives the missed evaporation loss in the High Dam reservoir directly, according to two factors; the given month and the average monthly water level. This paper will explain how to get benefit from the available data of hydro-meteorological stations distributed within the High Dam reservoir, to predict the digital evaporation loss surface using the GIS prediction and conversion tools