A DIESEL ENGINE CONVERTED INTO OTTO CYCLE ENGINE: THE INFLUENCE OF THE SPARK ADVANCE ON ITS PERFORMANCE AND ON NOx EMISSIONS

This paper analyzes the performance of a diesel engine converted into an Otto cycle engine and its Nitrogen dioxide emissions in terms of the spark advance variation. The tests were conducted on a Perkins diesel engine 1104C - 44TAG turbocharged, whose compression ratio was reduced to 9.33:1. After conversion the engine started operating with liquefied petroleum gas (LPG) and running just with stoichiometric mixtures. The tests have been limited to 10 to 40 kW, always at 1800 rpm. During the experiments the ignition advance angle ranged from 5º up to 27º (BTDC), using the increment of 5°, whenever possible. Particularly at 40 kW, the range of the ignition advance was 15º to 20º. The results showed a significant influence of the spark advance angle on the fuel consumption, on the temperature and on the NOx emissions, as well as on the magnitude of the generated power

ELECTRICITY GENERATION FROM BIOMASS GASIFICATION

Brazil is among the ten largest consumers of electricity in the world, and in the last decades its demand for electricity has been continuously increasing. As a consequence it has not been capable to ensure enough expansion of its electric power network, mostly affecting isolated communities. The present study discusses the use of a system formed by an Indian residue biomass gasifier and a 36 kVA engine-generator, which should generate 20 kWe, using gas-alone mode engine. The engine was, originally, a MWM D229-4 diesel engine, which was converted into an Otto cycle to run only with producer gas. The system performance was evaluated for different engine’s advance ignition angles, and two types of biomass. As the Indian gasifier was designed to operate just with dual-fuel mode to feed a gas-alone engine, some changes in the gasifier's water cleaning system were required. The modifications enabled the system to improve the power generation which overcame the 20 kWe reaching 26 kWe. Technical and economic considerations showed that the bioelectricity based on bio-residual gasifier may be a viable and ecological option for regions having enough biomass residue and not served by the system network

CONVERSION OF TURBOCHARGED DIESEL ENGINE TO OPERATE SOLELY WITH HYDROUS ETHANOL

This paper discusses the conversion of a turbocharged diesel engine to operate with hydrous ethanol, using procedures developed in Innovation Lab of UFPB, IL. An diesel engine, brand Perkins, model 1104C-44TAG2, was converted to operate with hydrous ethanol at the time that it amended its compression ratio of 18:1 to 9.3:1, suitable for an Otto Cycle engine to non-occurrence of detonation fuel. Comparing experimental data generated for the converted engine tests (which ranged the ignition advance, stoichiometric air/fuel ratio and rotation at 1800 rpm) with those obtained in tests with the original engine, and converted, 45 kWe, a cost reduction of 34% with Ignition Advance of 20°. It was taken into account in this analysis, and data on fuel consumption, the cost of diesel, R$1.90/liter, and hydrous ethanol, R$ 0.70/liter. Regarding the gaseous emissions, depending on the load, it was found that the NOX ranged from 50 to 1050 ppm, CO, 1 to 3%, CO2, 12 to 15% and HC 150 to 450 ppm

Active phloem sap collection by Trigona spinipes (Fabricius) (Hymenoptera, Apidae) in Artemisia annua Linn (Asteraceae).

Abstract: Trigona spinipes Fabricius (Apidae: Meliponini), is a common stingless bee widely seen in urban and rural areas in Brazil, popularly known as irapuá, arapuá or bee-dog. Although these bees are considered pollinators of some cultivated plants, they are better known for the damage they cause in different crops. During experimental agroecological cultivation of Artemisia (Artemisia annua Linn, Asteraceae), in Jaguariúna (SP, Brazil), stingless bees Trigona spinipes (Fabricius) were observed sucking phloem sap directly from the plant, a phenomenon not yet described in scientific literature. This study aimed to register and describe the phloem sap-sucking behavior performed by T. spinipes for the first time, as well as to assess the potential impact of this behavior on A. annua cultivation. The behavior and the material collected by bees and the severity of attack were also analyzed. The aging and premature death of observed A. annua specimens occurred because of extensive lesions caused by T. spinipes, confirming the negative consequence of sap-sucking attacks of T. spinipes bees on the plants. Factors that could induce this unusual behavior were presented, pointing out the need for future studies on the development of strategies to protect plants, without causing damage to the T. spinipes bee populations, which are elements of Brazilian bee fauna and, therefore, protected by law

Paracrine effect of carbon monoxide - astrocytes promote neuroprotection through purinergic signaling in mice

© 2016. Published by The Company of Biologists Ltd.The neuroprotective role of carbon monoxide (CO) has been studied in a cell-autonomous mode. Herein, a new concept is disclosed - CO affects astrocyte-neuron communication in a paracrine manner to promote neuroprotection. Neuronal survival was assessed when co-cultured with astrocytes that had been pre-treated or not with CO. The CO-pre-treated astrocytes reduced neuronal cell death, and the cellular mechanisms were investigated, focusing on purinergic signaling. CO modulates astrocytic metabolism and extracellular ATP content in the co-culture medium. Moreover, several antagonists of P1 adenosine and P2 ATP receptors partially reverted CO-induced neuroprotection through astrocytes. Likewise, knocking down expression of the neuronal P1 adenosine receptor A2A-R (encoded by Adora2a) reverted the neuroprotective effects of CO-exposed astrocytes. The neuroprotection of CO-treated astrocytes also decreased following prevention of ATP or adenosine release from astrocytic cells and inhibition of extracellular ATP metabolism into adenosine. Finally, the neuronal downstream event involves TrkB (also known as NTRK2) receptors and BDNF. Pharmacological and genetic inhibition of TrkB receptors reverts neuroprotection triggered by CO-treated astrocytes. Furthermore, the neuronal ratio of BDNF to pro-BDNF increased in the presence of CO-treated astrocytes and decreased whenever A2A-R expression was silenced. In summary, CO prevents neuronal cell death in a paracrine manner by targeting astrocytic metabolism through purinergic signaling.publishersversionpublishe

Preconditioning triggered by carbon monoxide (CO) provides neuronal protection following perinatal hypoxia-ischemia

Perinatal hypoxia-ischemia is a major cause of acute mortality in newborns and cognitive and motor impairments in children. Cerebral hypoxia-ischemia leads to excitotoxicity and necrotic and apoptotic cell death, in which mitochondria play a major role. Increased resistance against major damage can be achieved by preconditioning triggered by subtle insults. CO, a toxic molecule that is also generated endogenously, may have a role in preconditioning as low doses can protect against inflammation and apoptosis. In this study, the role of CO-induced preconditioning on neurons was addressed in vitro and in vivo. The effect of 1 h of CO treatment on neuronal death (plasmatic membrane permeabilization and chromatin condensation) and bcl-2 expression was studied in cerebellar granule cells undergoing to glutamate-induced apoptosis. CO's role was studied in vivo in the Rice-Vannucci model of neonatal hypoxia-ischemia (common carotid artery ligature +75 min at 8% oxygen). Apoptotic cells, assessed by Nissl staining were counted with a stereological approach and cleaved caspase 3-positive profiles in the hippocampus were assessed. Apoptotic hallmarks were analyzed in hippocampal extracts by Western Blot. CO inhibited excitotoxicity-induced cell death and increased Bcl-2 mRNA in primary cultures of neurons. In vivo, CO prevented hypoxia-ischemia induced apoptosis in the hippocampus, limited cytochrome c released from mitochondria and reduced activation of caspase-3. Still, Bcl-2 protein levels were higher in hippocampus of CO pre-treated rat pups. Our results show that CO preconditioning elicits a molecular cascade that limits neuronal apoptosis. This could represent an innovative therapeutic strategy for high-risk cerebral hypoxia-ischemia patients, in particular neonates

Pemetrexed na segunda linha de tratamento do carcinoma do pulmão de não pequenas células – A experiência portuguesa

AbstractUntil 2004, docetaxel in monotherapy was the standard for second-line treatment of non-small cell lung cancer (NSCLC). Pemetrexed (P) has shown similar activity in this setting with a better adverse event profile. In Portugal, it was introduced in October of 2004.We have carried out a retrospective analysis of patients (pts) who received P for second-line NSCLC in Portugal from October 2004 to December 2006. Data were collected from the records of pts with locally advanced or metastatic NSCLC and failed first-line chemotherapy enrolled in centers participating in the Portuguese Lung Cancer Study Group (GECP). Objective response (OR; complete [CR] or partial [PR] response) was evaluated using RECIST and safety was assessed using serious or non-serious adverse events (SAEs/AEs).By December 2006, 19 GECP centers had enrolled 244 pts who had received P for ≥1cycle, and were considered evaluable for both objective response and safety. Demography: male/female, 175/69; median age, 57.0years (range 20-81); smoking status, y/ex/n, 116/57/71; adenocarcinoma / squamous-cell carcinoma/other histology, 141/72/31; mean time to progression (TTP) 8.07months. Disease control in 209 evaluable pts was observed in 116 (55.5%): 2 CR, 45 PR and 69 SD; mean TTP 4.70months. The majority of AEs were grade 3 anemia (15 pts) and neutropenia (18 pts). The mean overall survival was 17.27months.Our retrospective analysis has observed a similar disease control rate with P in 2nd line (55.5%), and TTP (4.7months) in our current unselected population to that published in the literature. P is an option for second-line NSCLC with a good tolerability.Rev Port Pneumol 2008; XIV (Sup.2): S9-S2

Sistemas biodiversos em assentamentos rurais: monitoramento, papel do conhecimento e especulações sobre políticas públicas.

No presente escrito são descritas as ações da Equipe de Agroecologia da Embrapa Meio Ambiente na construção do conhecimento agroecológico em assentamentos rurais do Estado de São Paulo, indicando fases, métodos e impactos ecológicos e socioeconômicos no âmbito dos lotes. O foco destas ações foi a implantação de sistemas biodiversos, na forma de agroflorestas. Posteriormente a equipe desenvolveu diversos esforços para conceber e aplicar planos de monitoramento dos sistemas manejados. A fase inicial de evolução deste empreendimento resultou em interessantes dados qualitativos sobre diversos aspectos dos sistemas agroflorestais. O trabalho finaliza pontuando questões emergentes e desafios como o de desenvolver e validar estratégias metodológicas de análise integrada de sistemas agroecológicos biodiversos como base para reforçar sua estabilidade, sua aplicação socialmente ampliada e sua consolidação econômica, sócio-cultural e política

Produção e qualidade do leite de cabra no Brasil.

Neste documento será feita uma caracterização da caprinocultura leiteira no Brasil e discutidos aspectos qualitativos com foco em oportunidades de crescimento sustentável para a cadeia