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[en] We developed an optimization model for determining thinning schedules in planted teak (Tectona grandis L.f.) stands that maximize the financial output in terms of soil expectation value (SEV) and net present value (NPV) considering a) the simultaneous optimization of timber production and carbon (C) sequestration and b) only for C sequestration. Planted teak forests in the western alluvial plains of Venezuela. We integrated a stand growth and yield model with a constrained optimization model based on genetic algorithms (GA) for determining optimal thinning schedules (number, age, and removal intensity) that maximize SEV when simultaneously managing for timber production and C sequestration. The data came from permanent plots established in planted teak stands with remeasurements from 2 to 32 yr.-old. Plots differ in site quality, initial spacing, and thinning schedules. We obtained optimal thinning schedules for several scenarios combining site quality, initial spacing, interest rates, harvest and transport costs, as well as timber and C prices. The stand growth and yield model estimates timber products and C flows (storage and emissions) until most stored C is reemitted to the atmosphere. When considering simultaneously both, timber production and C sequestration, the scenario with the maximum SEV consisted of initial stand densities = 1,111 trees ha-1, site quality (SQ) I, harvest age 20 years, and four thinnings (ages 6, 10, 14, 17 with removal intensities 26 %, 28 %, 39 %, and 25 % of stand basal area respectively). For maximizing C sequestration only, the best schedule consisted of 1,600 trees ha-1, SQ I, harvest age 25 years, with no-thinning. A sensitivity analysis showed that optimal schedules and SEV were highly sensitive to changes in interest rates, growth rates, and timber prices.
[en] Ion sources are devices which generate ions of atoms of interest which can be extracted as an ion beam by applying suitable extraction method. An ideal ion source shall produce high intensity ions with a minimum emittance for the experimental interest. The development of such low emittance ion sources have a great contemporary significance. They are used for various purposes such as radioactive ion beam production and sophisticated nuclear astrophysics experiments. Keeping the above facts in view, to produce a low emittance, high intensity ion beam, a low temperature plasma has been generated. Further the ion transport has been verified through simulation studies for understanding the extracted beam properties
[en] In pair production, particle and antiparticle are generated when energy form mass and mass form dipole and then separation take place in stronger nuclear filed. After the formation of mass, it goes on oscillation and oscillation causes the dipole creation on mass which further goes on separation from each other as and Q1E3X «Q2E3(X´-X) moreover the forces F32>>F31. These two component play major role for the separation of the masses in oscillation time having frequency (f). Also with the help of size of nucleus and atom, the maximum distance and maximum time for pair production 9.99 x 10-11m and 3.33 x 10-19s, respectively, has been calculated
[en] Nuclear emulsion detector played important role in the studies of high energy interactions during the twentieth century. In this report, the focus is on the characteristics of the shower particles produced in the interaction of 84Kr with nuclear emulsion detector at relativistic energy
[en] To commemorate the 500th anniversary of the city of Havana, the Isotope Center reviews its activity since its creation. The production of radionuclidemarked compounds and other radiochemical work at the Institute of Nuclear Physics, inaugurated in 1969, stimulated the applications of open radioactive sources, which can be considered as the most tangible organized antecedent of the center. Later in the 1980s, the Executive Secretary for Nuclear Affairs accelerated, diversified and expanded nuclear applications, developed the training of highly qualified staff and experts as well as international cooperation. The creation of the Center for Applied Nuclear Development Studies coincided with the consolidation of a group of biotechnological research and production institutions and with these applications gaining importance in Nuclear Medicine. It was soon recognized that it was not possible to continue managing a growing inventory of radionuclides. As a result, CENTIS, a specialized center with a complete cycle, was designed and built, which comprised not only research and development, but also production and marketing. When in 1994 CENTIS became part of the Nuclear Energy Agency, investment was concluded and the production methodologies of the most important radiopharmaceuticals were established. In more than 20 years of work CENTIS has become the main support of Nuclear Medicine in the country. With its metrological capabilities in the magnitude of radioactivity and its non-clinical and clinical research, it is increasingly part of the socio-economic life of the country and its capital. In this paper the main results of each stage are detailed in relation to the mission of the center and a technical assessment is made regarding the actions taken to favor their target sectors: health and biomedical research. Periods of five years in favor of centuries.
[en] Highlights: • This paper examines the economic impact of the increased energy taxes in Vietnam. • The increased tax on petroleum considerably affects the country. • The new tax on petroleum reduces the emissions level at relative low rates. • A rise in tax on coal slightly affects Vietnam but reduces substantial emissions. - Abstract: The Vietnamese Government is proposing a new tax levy on either petroleum products or coal, or both. That is, the Government expects to increase the current tax rates to the maximum levels set previously. In this instance, the tax on coal is intended to increase by 50%, while the tax on petroleum products is intended to increase by 33.33%. This study employs a computable general equilibrium model to assess the effects of these increases in taxes on the Vietnamese economy, focusing on energy, transportation, and the private sectors. Results show that an increase in tax on petroleum products will considerably affect the country with a reduction of real GDP by 1.99%. Exports and imports are also highly unfavorably affected. In this instance, the total emission level will be reduced by 7.12%. The increased tax on coal, however, will allow Vietnam to experience much lower unfavorable effects, while being able to cut a substantial amount of the emission level. For example, real GDP would only decline by 0.51%, while total emission level will be reduced by 10.25%. If these taxes are increased together, Vietnam will experience considerable contractions in the economy, but it is able to reduce a substantial emission level.
[en] Highlights: • Waste frying oil was successfully used as an inhibitor for H2 consumption during dark fermentation of mixed cultures. • Methane production in pre-treated cultures decreased significantly. • Duration of pre-treatment and concentration of waste frying oil affected H2 production. • Volatile fatty acids accumulation increased with waste frying oil concentration. - Abstract: An innovative method was introduced to inhibit methanogenic H2 consumption during dark fermentative hydrogen production by anaerobic mixed cultures. Waste frying oil was used as an inhibitor for hydrogenotrophic methanogens. Simultaneous effect of waste frying oil concentrations (0–20 g/L) and initial pH (5.5, 6.5 and 7.5) on inhibition of methanogenic H2 consumption and enhancement of H2 accumulation were investigated using glucose as substrate. Enhanced hydrogen yields with decreased methane productions were observed with increasing the waste frying oil concentrations. On average, CH4 productions from glucose in the cultures received 10 g/L WFO were reduced by 88%. Increased WFO concentration up to 20 g/L led to negligible CH4 productions and in turn enhanced H2 yields. Hydrogen yields of 209.26, 195.35 and 185.60 mL/g glucoseadded were obtained for the cultures pre-treated with 20 g/L waste frying oil with initial pH of 5.5, 6.5 and 7.5 respectively. H2 production by pre-treated cultures was also studied using a synthetic food waste. Anaerobic mixed cultures were pre-treated with 10 g/L WFO and varying durations (0, 24 and 48 h). A H2 yield of 71.46 mL/g VS was obtained for cultures pre-treated with 10 g/L WFO for 48 h that was 475% higher than untreated control. This study suggests a novel and inexpensive approach for suppressing hydrogenotrophic methanogens during dark fermentative H2 production.