Laser Damage Thresholds of Several Metal-Containing Acrylic Polymers at Four Different Wavelengths.

1991 ◽  
Vol 236 ◽  
Author(s):  
Pearl W. Yip
Keyword(s):  
Electron Spectroscopy ◽  
Light Transmission ◽  
Single Pulse ◽  
Laser Damage ◽  
Laser Materials ◽  
Acrylic Polymers ◽  
Multiple Pulse ◽  
Chemical Damage ◽  
Before And After ◽  
Physical And Chemical

AbstractSingle- and multiple-pulse laser damage thresholds of six different metal-containing acrylic polymers were determined at 10.6, 1.06, 0.53 and 0.355 μm. Light transmission of these samples before and after irradiation was measured. A variety of observed laser-materials interactions are discussed in this paper. Physical and chemical damage properties of these metal-containing acrylic polymers were examined and compared with poly (methyl methacrylate) and polycarbonate using scanning electron microscopy (SEM), infrared spectroscopy (IR), and electron spectroscopy for chemical analysis (ESCA). In general, it was found that the multiple-pulse damage thresholds were lower than the single-pulse, and damage thresholds decreased as wavelength of the testing laser beam became shorter.

scholarly journals Effect of natural disinfectant (Moringa oleifera) and a chemical disinfectant (calcium hypochlorite) on nematode eggs: bioefficiency and impact of physico-chemical variables

2020 ◽  
Vol 10 (2) ◽  
pp. 335-346
Author(s):  
Arnold Landry Fotseu Kouam ◽  
Gideon Aghaindum Ajeagah
Keyword(s):  
Petri Dish ◽  
Nematode Species ◽  
Optical Microscope ◽  
Chemical Parameters ◽  
Calcium Hypochlorite ◽  
Physico Chemical ◽  
Before And After ◽  
Nematode Eggs ◽  
Chemical Disinfectant ◽  
Physical And Chemical

Abstract The aim of this study is to determine the effectiveness of disinfectant on the viability of eggs from three nematode species (Ascaris, Trichuris, Ankylostoma). It was conducted in a microcosm from June 2018 to June 2019. The wastewater scan was sampled using 5 L sterile containers, the sample was arranged in four replicas, three tests and one control. The test samples received three disinfectants (Moringa, calcium hypochlorite and Moringa associated with calcium hypochlorite) at varying concentrations. The physical and chemical parameters were measured before and after the application of each disinfectant. The samples were then observed under an optical microscope. The viability of the eggs was determined by incubating the Petri dish samples at 30 °C for 30 days. The analyses show that some physicochemical parameters can significantly influence the efficacy of disinfectant on the eggs. The calcium hypochlorite associated with Moringa at 0.6 g/L showed greater efficacy on reducing viability and inactivation of eggs with 100% efficacy yield rates on Ankylostoma and Trichuris trichiuria and 97% on Ascaris lumbricoides eggs; this efficacy is significantly different from that observed on samples treated with Moringa and simple calcium hypochlorite. Of the three parasites tested, A. lumbricoides showed greater resistance to the disinfectant.

Identification of Amber and the Copal under Heat Pressurized Process

2012 ◽  
Vol 554-556 ◽  
pp. 2112-2115
Author(s):  
Hui Li ◽  
Xuan Wang ◽  
Yong Zhu ◽  
Qin Ren
Keyword(s):  
Chemical Properties ◽  
Peak Position ◽  
Exothermic Peak ◽  
Endothermic Peak ◽  
Scanning Calorimetry ◽  
Natural Resin ◽  
Before And After ◽  
Artificial Heat ◽  
Physical And Chemical ◽  
And Chemical Properties

Amber and copal belong to the natural resin, which are similar and transitional in the physical and chemical properties. The artificial heat-pressurized treatment is contributed to the polymerization of the natural copal, and turns into green, yellow-green and deep orange-yellow copal. It is very difficult to identify amber from the heat- pressurized treatment copal only based on the gemological parameters.The thermal behavior of amber and the copal before and after heat-pressurized treatment were analyzed by means of differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy(FTIR) and nuclear magnetic resonance(NMR). The results show that amber exists an evident endothermic peak around 123~132°C, and copal reveals an obvious endothermic peak at about 174~178°C, and the heat pressurized treatment copal occurs a clear exothermic peak around 150~152°C. The differences between endothermic or exothermic transition and peak position reveal occurring thermal oxidation or the bond breaking or the melting, which are of great significance in the identification.

scholarly journals Modeling Perfusion Dynamics in the Skin During Iontophoresis of Vasoactive Drugs Using Single-Pulse and Multiple-Pulse Protocols

2015 ◽  
Vol 22 (6) ◽  
pp. 446-453 ◽  
Author(s):  
Fredrik Iredahl ◽  
Veeranjaneyulu Sadda ◽  
Liam J. Ward ◽  
Johannes Hackethal ◽  
Simon Farnebo ◽  
...  
Keyword(s):  
Single Pulse ◽  
Vasoactive Drugs ◽  
Multiple Pulse

scholarly journals Fungi and mycotoxins: Food contaminants

2013 ◽  
Vol 67 (4) ◽  
pp. 639-653 ◽  
Author(s):  
Suncica Kocic-Tanackov ◽  
Gordana Dimic
Keyword(s):  
Animal Origin ◽  
Food Contaminants ◽  
Penicillium Species ◽  
Nutritive Quality ◽  
Vegetable Products ◽  
Before And After ◽  
Biologic Effects ◽  
Food Species ◽  
Food Sterilization ◽  
Physical And Chemical

The growth of fungi on food causes physical and chemical changes which, further affect negatively the sensory and nutritive quality of food. Species from genera: Aspergillus, Penicillium, Fusarium, Alternari?, Cladosporium, Mucor, Rhizopus, Eurotium and Emericella are usually found. Some of them are potentially dangerous for humans and animals, due to possible synthesis and excretion of toxic secondary metabolites - mycotoxins into the food. Their toxic syndroms in animals and humans are known as mycotoxicoses. The pathologic changes can be observed in parenhimatic organs, and in bones and central nervous system also. Specific conditions are necessary for mycotoxin producing fungi to synthetize sufficient quantities of these compounds for demonstration of biologic effects. The main biochemical paths in the formation of mycotoxins include the polyketide (aflatoxins, sterigmatocystin, zearalenone, citrinine, patulin), terpenic (trichothecenes), aminoacid (glicotoxins, ergotamines, sporidesmin, malformin C), and carbonic acids path (rubratoxins). Aflatoxins are the most toxigenic metabolites of fungi, produced mostly by Aspergillus flavus and A. parasiticus species. Aflatoxins appear more frequently in food in the tropic and subtropic regions, while the food in Europe is more exposed to also very toxic ochratoxin A producing fungi (A. ochraceus and some Penicillium species). The agricultural products can be contaminated by fungi both before and after the harvest. The primary mycotoxicoses in humans are the result of direct intake of vegetable products contaminated by mycotoxins, while the secondary mycotoxicoses are caused by products of animal origin. The risk of the presence of fungi and mycotoxin in food is increasing, having in mind that some of them are highly thermoresistent, and the temperatures of usual food sterilization is not sufficient for their termination. The paper presents the review of most important mycotoxins, their biologic effects, the condition of their synthesis, occurence in food, permitted tolerant intake, as well as the possibility of their degradation.

scholarly journals Cashew Growth and Canopy Dynamics as Influenced by Manuring in a Guinea Savanna Agro-Ecology of Nigeria

2020 ◽  
pp. 80-88
Author(s):  
Beatrice Abanum Nduka ◽  
Olorunfemi Sunday Ojo Akanbi ◽  
Idrisu Mohammed ◽  
Seun Adewale Adeosun ◽  
Osasogie Ugioro ◽  
...  
Keyword(s):  
Block Design ◽  
Organic Fertilizer ◽  
Chemical Properties ◽  
Soil Nutrient ◽  
Ground Cover ◽  
Canopy Development ◽  
Canopy Volume ◽  
Before And After ◽  
Soil Status ◽  
Physical And Chemical

A two-year experiment was conducted to study the response of manuring on growth and canopy development on three-year-old Cashew trees. The experiment was laid in a randomized complete block design, with three replications. Soil characteristics including the chemical and physical properties were analyzed before and after the experiments. Fecti-plus organic pelletized fertilizer was applied at different rates of 0,750.6 and 1,501.2 kg/ha-1 respectively around the circumference of the tree. Before the application, the fertilizer sample was also analyzed. Data collected were plant height, stem girth, canopy dynamics which includes: Canopy diameter, canopy radius, canopy spread (North-South and East-West directions), canopy volume, canopy ground cover and percentage ground cover. The results from the pre soil sample show a relatively low status but were significantly enhanced after the application of the pelletized organic fertilizer (Ferti-plus). The soil nutrient composition of Oc, Om, N, K, Na, Ca and Mg+ was significantly highest in the plots having 1,501.2 kg/ha-1 treatments. Generally, there was a significant increase in the soil nutrient with the addition of pelletized fertilizer in respective of the rate of application. Also the results on the canopy dynamic in terms of canopy volume, spread and diameter revealed better development with the use of 1501.2 kg/ha-1 pelletized fertilizer and significantly different to 750.6 kg/ha-1 and those in the no-manure (control)plots. Meanwhile, the use of pelletized organic fertilizer gave superior growth and canopy development. It also influenced the growth of the Cashew plants, as well as the physical and chemical properties of the soil status.

scholarly journals Produksi Biofuel Dari Limbah Cpo Dengan Katalis Berbasis Titanium Oksida Dan Implementasinya Pada Pembelajaran Kimia

2017 ◽  
Vol 1 (1) ◽  
pp. 19-24
Author(s):  
Nurlia Latifah ◽  
Agus Sundaryono ◽  
Rina Elvia
Keyword(s):  
Methyl Ester ◽  
Learning Outcomes ◽  
Alternative Energy ◽  
Chemical Properties ◽  
Student Learning Outcomes ◽  
Tio2 Catalyst ◽  
Before And After ◽  
Cracking Process ◽  
Physical And Chemical ◽  
And Chemical Properties

Conversion of CPO waste into biofuel is one of the efforts to find alternative energy to overcome Indonesia's energy crisis. The resulting methyl ester was further processed into biofuel by cracking process with Ni/TiO2 and Co/TiO2 catalysts at temperature > 350oC for 2.5 hours followed by distillation. Educational research was done by doing the learning process by using biofuel module. The optimum biofuel yield was obtained from cracking methyl ester with 5% Ni/TiO2 catalyst and 3% Co/TiO2 catalyst respectively of 66,67 and 61,90%. The physical and chemical properties of cracked biofuels with Ni/TiO2 and Co/ TiO2 catalysts have complied with ASTM standards for biofuel except acid numbers. There is an increase in student learning outcomes before and after using the module. 

Non-responsiveness of serum gonadotropins and testosterone to pulsatile GnRH in hemochromatosis suggesting a pituitary defect

1993 ◽  
Vol 128 (4) ◽  
pp. 351-354 ◽  
Author(s):  
Lise Duranteau ◽  
Philippe Chanson ◽  
Joelle Blumberg-Tick ◽  
Guy Thomas ◽  
Sylvie Brailly ◽  
...  
Keyword(s):  
Single Pulse ◽  
Serum Testosterone ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Gonadotropin Secretion ◽  
Pulsatile Gnrh ◽  
Serum Lh ◽  
Before And After ◽  
Gnrh Therapy ◽  
Lh Secretion

We investigated the potential pituitary origin of gonadal insufficiency in hemochromatosis. Gonadotropin secretion was studied in seven patients with hemochromatosis and hypogonadism, before and after chronic pulsatile GnRH therapy. Pulsatile LH secretion was studied before (sampling every 10 min for 6 h) and after 15-30 days of chronic pulsatile GnRH therapy (10-12 μg per pulse). Prior to GnRH therapy, all the patients had low serum testosterone, FSH and LH levels. LH secretion was non-pulsatile in four patients, while a single pulse was detected in the remaining three. Chronic pulsatile GnRH administration did not increase serum testosterone levels; similarly, serum LH levels remained low: neither pulse frequency nor pulse amplitude was modified. We conclude that hypogonadism in hemochromatosis is due to pituitary lesions.

Properties of defect-induced multiple pulse laser damage of transmission components

2016 ◽  
Vol 55 (25) ◽  
pp. 7078 ◽  
Author(s):  
Bin Ma ◽  
Li Zhang ◽  
Menglei Lu ◽  
Ke Wang ◽  
Hongfei Jiao ◽  
...  
Keyword(s):  
Pulse Laser ◽  
Laser Damage ◽  
Multiple Pulse

Multiple Pulse Irradiation Effects in Excimer Laser-Induced Crystallization of Amorphous Si Films

1993 ◽  
Vol 321 ◽  
Author(s):  
H. J. Kim ◽  
James S. Im
Keyword(s):  
Excimer Laser ◽  
Single Pulse ◽  
Pulse Irradiation ◽  
Multiple Pulse ◽  
Melting Phenomenon ◽  
Irradiation Energy ◽  
Crystallization Experiments ◽  
Amorphous Si ◽  
Si Films ◽  
Induced Crystallization

ABSTRACTWe have experimentally Investigated the effects that are associated with Multiple-pulse irradiation in the excimer laser processing of thin Si films on SiO2. Double-pulse irradiation experiments revealed results, which are consistent with that which is known from single-pulse crystallization experiments, and these experiments confirm the applicability of the transformation scenarios, which were derived from single pulse-induced crystallization experiments [1,2]. The results from the Multiple-pulse irradiation experiments clearly show that gradual and substantial grain enlargement can occur — and only occurs — when the irradiation energy density is close to but less than the level that is required to melt the film completely. Based on these findings, we argue that the grain enlargement effect is a near-complete melting phenomenon that is associated with polycrystalline Si films, and we present a grain boundary melting model to account for this phenomenon. A brief discussion on the apparent similarities and physical differences between the observed phenomenon and the solid state grain growth processes is provided herein.

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