WHEAT SEED AND AGRICULTURE PROGRAMMING IN AFGHANISTAN: ITS POTENTIAL TO IMPACT ON LIVELIHOODS

Agricultural and Food Policy, Teaching/Communication/Extension/Profession,

Even Better than the Real Thing

In an era where the youth were obsessed with an appearance of success and being hip, when Coke finally altered its New Coke brand identity to appeal to the youth, they still could not make the youth accept New Coke. In the end when Coke had the chance to market to the trendy Generation X in 1985, they focused on taste instead of adapting the brand to fit youth trends. When they finally changed the strategy to appeal to the youth, it was far too late. The “smart shoppers” of the 1980s had already identified New Coke as a failure and moved on

Karakterisasi karbon aktif dari Green Coke dengan perlakuan kimia (Na OH).

Green coke adalah hasil sainping dari destruksi minyak meritah, yang pemanfaatannya sebagiari besar sebagai bahan bakar. Untuk menambah riilai ekonomisnya maka perlu dilakukan pengembangan potensi lain dari green coke yaitu sebagai karbon aktif. Telah dibuat karbon aktif dari green coke dengan perlakuan kimia t'TaOH ,sienganyariasi00,1 H, 0,5 N, 1,0 N dengan temperatur 350 C, 450 C, 550 C, 650c, C. Karbcn aktif hasil percobaan untuk yang terbaik diperoieh pada NaOH sebesar 1,0 N dengan temperatur 650 C dengan kadar air 4,465 %; zat volatile matter 9,295 %; kadar abu 2,927 %; kadar karbon murni 83,085 %; daya scrap terhadap metileri Flue 8,25 ml/gram clan luas permukaan sebesar 51,1349 m is gram. Green coke is the residue of the destructive of crude oil , the mayor uses of green •coke is the burning material, to increase the economic value , it mustbe to developed to use of active carbon. Activated carbon have been made from green coke with NaOH chemical treatment with variety 400,1 N, N and temperature variety is 350°C, 450 C, 550°C, 650°C. C. Characterization for yield activated carbons could be obtained the best for KA 1,0 N NaOH - 650,C with _Moisture 4,645 %, Volatile Matter 9,295 %, Ash Content 2,975 %, Fixed' Carbon 83,085 % , Adsorption getilen of Blue 8,25 ml / gram and Surface area 51,1349 m/ gram

Urinary naphthalene and phenanthrene as biomarkers of occupational exposure to polycyclic aromatic hydrocarbons.

OBJECTIVES: The study investigated the utility of unmetabolised naphthalene (Nap) and phenanthrene (Phe) in urine as surrogates for exposures to mixtures of polycyclic aromatic hydrocarbons (PAHs). METHODS: The report included workers exposed to diesel exhausts (low PAH exposure level, n = 39) as well as those exposed to emissions from asphalt (medium PAH exposure level, n = 26) and coke ovens (high PAH exposure level, n = 28). Levels of Nap and Phe were measured in urine from each subject using head space-solid phase microextraction and gas chromatography-mass spectrometry. Published levels of airborne Nap, Phe and other PAHs in the coke-producing and aluminium industries were also investigated. RESULTS: In post-shift urine, the highest estimated geometric mean concentrations of Nap and Phe were observed in coke-oven workers (Nap: 2490 ng/l; Phe: 975 ng/l), followed by asphalt workers (Nap: 71.5 ng/l; Phe: 54.3 ng/l), and by diesel-exposed workers (Nap: 17.7 ng/l; Phe: 3.60 ng/l). After subtracting logged background levels of Nap and Phe from the logged post-shift levels of these PAHs in urine, the resulting values (referred to as ln(adjNap) and ln(adjPhe), respectively) were significantly correlated in each group of workers (0.71 < or = Pearson r < or = 0.89), suggesting a common exposure source in each case. Surprisingly, multiple linear regression analysis of ln(adjNap) on ln(adjPhe) showed no significant effect of the source of exposure (coke ovens, asphalt and diesel exhaust) and further suggested that the ratio of urinary Nap/Phe (in natural scale) decreased with increasing exposure levels. These results were corroborated with published data for airborne Nap and Phe in the coke-producing and aluminium industries. The published air measurements also indicated that Nap and Phe levels were proportional to the levels of all combined PAHs in those industries. CONCLUSION: Levels of Nap and Phe in urine reflect airborne exposures to these compounds and are promising surrogates for occupational exposures to PAH mixtures

Influence of the catalyst support on the steam reforming performance of toluene as tar model compound

The large amount of tar produced along with the syngas during biomass gasification is one of the major obstacle for the diffusion of gasifiers at industrial scale. Catalytic cracking and reforming are the most suitable processes for the transformation of tar into lighter gases. The selection of suitable catalysts is a critical step. The catalysts must own high activity and high resistance to deactivation for coke deposition. In this work the effect of two different supports, mayenite and aluminium oxide, on the activity of the nickel was investigated in the steam reforming of toluene that was used as tar model compound. In particular, the performed experimentations aimed to test the mayenite in terms of improvement of resistance to carbon deposition in conditions similar to those of gasification reactors. The obtained results indicate that Ni /mayenite catalyst needs higher temperature to activate and leads to lower value of toluene conversion with respect to Ni / alumina. However, mayenite, which is known from literature to have higher resistance to coke deposition due to the presence of free oxygens in the lattice which oxidize the coke deposited on the catalyst surface showed higher resistance to deactivation especially for low steam to carbon ratios

On the deactivation of Zr-loading P-containing mesoporous carbon catalyst during methanol dehydration

Dimethyl ether (DME) has received much attention in the last few years due to its potential use as a diesel substitute and it can be obtained from dehydration of biomass-based methanol. γ-Alumina, ZSM-5 and HPAs were tested as catalysts. A carbon-supported zirconium phosphate catalyst was synthesized and tested for methanol dehydration reaction in a high temperature range. Carbon matrix was produced by olive stone waste activated with phosphoric acid (mass acid to olive stone ratio of 2:1) at 800ºC for 2 h. Then, after washing with distilled water and sieving between 100-300μm, the obtained carbon was impregnated with ZrO(NO3)2 and thermal treated at 250ºC for 2 h. Reaction was performed in a fixed-bed reactor at a space time of 75 gcat·s/mmolCH3OH, a partial pressure of 0.04 atm of methanol and temperatures between 450-600ºC. Deactivated samples were exposed to air at 350ºC for 100 min to study the catalyst regeneration. The catalyst showed a high selectivity to DME (≥95%) and an acceptable conversion at Tª lower than 400ºC without noticeable deactivation. At T>400 ºC, deactivation was detected, due to coke deposition, whose rate increases with operating temperature. However, a high selectivity to DME was observed (above 65%) even at very long times on stream (tos). N2 adsorption results pointed out that deposition of coke took place mainly on the surface of the narrow micropores of the catalyst, blocking much of this narrow porosity at long tos. According to XPS analysis, superficial concentration of phosphorus and zirconium were also diminished with coke deposition, although zirconium was decreased to a larger extend. A kinetic model was developed for the catalyst deactivation during methanol dehydration under different reaction conditions, based on coke deposition.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Relevance of the composition of municipal plastic wastes for metallurgical coke production

This study is concerned with the effects of the composition of mixed plastic wastes on the thermoplastic properties of coal, the generation of coking pressure and the quality of the resulting cokes in a movable wall oven at semipilot scale. The mixed plastic wastes were selected to cover a wide spectrum in the relative proportions of high- and low-density polyethylenes (HDPE and LDPE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET). From the results it was deduced that the reduction in Gieseler fluidity in the coal blend is linked to the total amount of polyolefins in the waste. It was also found that these thermoplastics increase the pressure exerted against the wall in the course of the coking process and that coke quality is maintained or even improved. However, when the level of aromatic polymers such PS and PET are increased at the expense of polyolefins, the coking pressure decreases. Thus, the amount of aromatic polymers such as PS and PET in the waste is critical, not only for controlling Gieseler fluidity and coking pressure, but also for avoiding deterioration in coke quality (reactivity towards CO CRI and mechanical strength of the partially-gasified coke CSR). An amount of polyolefins in the waste lower than 65 wt.% for a secure coking pressure is established

Influence of silicon and silicon/sulfur-containing additives on coke formation during steam cracking of hydrocarbons

The influence of the combination of two Si-containing additives, BTMS and TEOS, with DMDS on coke formation during steam cracking has been evaluated both on a laboratory scale and in a pilot plant unit. Under the optimal presulfidation conditions (T = 1023 K, H2O = 20 g h(-1), DMDS in H2O = 750 ppm wt, duration = 1 h), the combination of Si pretreatment + presulfidation + continuous addition of 2 ppm wt DMDS results in a decrease in the rate of coke formation up to 40% when hexane is cracked in the lab-scale unit. Under similar conditions in the pilot plant the coke formation is decreased by 70%, while the CO production decreases by more than 90%. Moreover, the suppressing effect on coke formation remains significant even after several coking/decoking cycles. Simulations of an industrial ethane cracker indicate that the application of Si- and S-containing compounds as additives for the suppression of coke formation can potentially double the run length of industrial steam crackers

Deactivation of the catalyst during the MTO process from a molecular modeling perspective

Currently, the industrially important conversion process of methanol to olefins (MTO) forms a key process for the production of higher valued products that can easily be transported, such as ethylene and propylene. Methanol can be made from natural gas or coal via synthesis gas. Unraveling the underlying reaction mechanism of the complex MTO process has already shown to be very challenging. Recent ab initio calculations, in combination with experimental data, are in strong support of the “hydrocarbon pool model” as opposed to a direct (C-C coupling) route [1, 2]. The hydrocarbon pool has been described as a catalytic scaffold inside the zeolite building, consisting of polymethylbenzenes and their cationic derivatives. The continued growth of these initially active carbonaceous species within acidic zeolites, such as H-ZSM-5 and H-SAPO-34, is an undesired side effect resulting from secondary reactions for which at present no computational data exist whatsoever. The presence of these large species – coke precursors - inside or at the external cups of the periodic structure leads to blockage of the pores or channels and ultimately to the deactivation of the catalyst. An improved in-depth understanding of the underlying reaction mechanisms of coke formation is therefore desperately needed. A main problem is the generally poor characterization of coke, despite the great number of techniques (gas chromatography, mass spectroscopy) that can be used for locating and identifying the deposits [3, 4]. Because of this, it is not clear whether benzenoid species consisting of 3 rings can already be regarded as coke as opposed to large aromatic species present in the hydrocarbon pool that still allow an active route. Within this contribution possible reaction routes leading to the formation of naphthalene- and/or phenanthrene-like species are studied from theoretical viewpoint within various industrially relevant zeolite topologies. For each of these elementary steps reaction rates are evaluated based on energies and frequencies originating from reliable ab initio data. The latter were obtained by taking into account a large portion of the zeolites, as to be representative for the actual topology