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Optimization of the Pretreatment of the Mixture of Cassava Peelings and Pineapple Fibers Using Response Surface Methodology and a Process Simulator for the Bioethanol Production

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Energy and Power Engineering 2024年第2期16卷 79-96页

作者： Paul Nestor Djomou Djonga george Elambo Nkeng Madjoyogo Hervé Sirma Ahmat Tom Thierry Tchamba Tchuidjang Department of Textile and Leather Engineering National Advanced School of Engineering of Maroua Maroua Cameroon Department of Civil Environmental and Architectural Engineering University of Padova Padova Italy Institut du Génie des Systèmes Industriels et textiles Ecole Polytechnique de Ouagadougou Ouagadougou Burkina-Faso Department of Energy Engineering University Institute of Technology University of Ngaoundere Ngaoundere Cameroon Department of Process Engineering National Advanced School of Agro-Industrial Sciences University of Ngaoundere Ngaoundere Cameroon

The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production of bioethanol remains a challenge given the crystallinity of cellulose and the presence of the complex. The pretreatment aimed to solubilize the lignin fraction and to make cellulose more accessible to the hydrolytic enzymes, was done using the organosolv process. A mathematical modeling was performed to point out the effect of the temperature on the kinetics of the release of the reducing sugars during the pretreatment. Two mathematical model was used, SAEMAN’s model and Response surface methodology. The first show that the kinetic parameters of the hydrolysis of the cellulose and reducing sugar are: 0.05089 min-1, 5358.1461 j·mol-1, 1383.03691 min-1, 51577.6100 j·mol-1 respectively. The second model was used. Temperature is the factor having the most positive influence whereas, ethanol concentration is not an essential factor. To release the maximum, an organosolv pre-treatment of this sub-strate should be carried out at 209.08°C for 47.60 min with an ethanol-water ratio of 24.02%. Organosolv pre-treatment is an effective process for delignification of the lignocellulosic structure.

关键词： Bioethanol Cassava Peeling Pineapple Fibers Organosolv Process and Optimization

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跨世纪(时文博览) 2006年第2期 28-29页

作者： MICHAL j.collins

我的承诺我的病人,有一个人永远无法忘怀:莎拉·贝德森。我是在骨科肿瘤部遇上她的。莎拉当时才十八岁,貌美如花,但生命危在旦夕,骨盆左侧长了个骨骼肉瘤,情况并不乐观。比尔·柯莱默是主治医师。我们得告诉莎拉:她要活下去的唯一办法,... 详细信息

我的承诺我的病人,有一个人永远无法忘怀:莎拉·贝德森。我是在骨科肿瘤部遇上她的。莎拉当时才十八岁,貌美如花,但生命危在旦夕,骨盆左侧长了个骨骼肉瘤,情况并不乐观。比尔·柯莱默是主治医师。我们得告诉莎拉:她要活下去的唯一办法,是动大手术,切除左腿以及部分骨盆。

关键词：莎拉护士安妮骨盆手术室开刀房莱默医师麻醉师

采用状态检测系统改进重复使用火箭发动机的操作效率

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导弹与航天运载技术 1988年第9期 28-32页

作者： j.collins 王维彬

通过采用直接现场状态检测系统,可使重复使用的火箭发动机飞行任务的准备工作得到重大改进,并且可安全可靠地减少地面维修时间和费用。这些系统可在不分解发动机和手头上只有很少或几乎没有手册性的数据可供分析的情况下,通过采用一些... 详细信息

通过采用直接现场状态检测系统,可使重复使用的火箭发动机飞行任务的准备工作得到重大改进,并且可安全可靠地减少地面维修时间和费用。这些系统可在不分解发动机和手头上只有很少或几乎没有手册性的数据可供分析的情况下,通过采用一些新技术,对与发动机正常工作有关的元件进行连续的观测,直接测出这些关键元件的磨损情况。这些直接测量技术,可在有关元件的磨损还没影响整个发动机的性能以前,就及早地预报它们的损耗情况。将它们与发动机状态检测系统的计算机组合后,这些关键元件的测量结果为我们提供了一个不断更新的数据库,从而可为我们预测发动机是否可参与飞行提供依据,并可提前告诉我们是否需要提前维修。

关键词：发动机回收地面维修

Evaluation of alum-based water treatment residuals used to adsorb reactive phosphorus

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Water Science and Engineering 2020年第3期13卷 181-192页

作者： george Carleton Teresa j.Cutright Department of Civil Engineering The University of AkronAkronOH 44235-3905USA

Excess reactive phosphorus(PO4)in waterways can lead to eutrophication.A low-cost approach to reducing PO4 levels in surface water was evaluated using the alum-based water treatment residual(Al-WTR)or Al-WTR augmented with powdered activated carbon(PAC-WTR).Batch adsorption-desorption and continuous flow column experiments were performed to assess the specific adsorption capacities under various concentration and flow *** Al-WTR and PAC-WTR exhibited the ability to adsorb *** overall,cumulative sorbed amount after a 28-d desorption step for Al-WTR was 33.93 mg/kg,significantly greater than the PAC-WTR value of 24.95 mg/kg(p<0.05).The continuous flow column experiments showed a theoretical PO4 uptake of 9.00 mg/g for Al-WTR and 7.14 mg/g for PAC-WTR over 720 *** surface water was used,the Al-WTR and PAC-WTR columns removed 67.4%and 62.1%of the PO4,*** results indicated that Al-WTR was more effective for in-field evaluation.

关键词： Phosphorous Alum Water treatment residuals Adsorption Desorption Powered activated carbon

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在融合的VPN方案中实现报告和控制功能

网络电信 2006年第11期8卷 21-24页

作者： j.collins K.Frank

企业接受托管式通信业务的前提是运营商在他们提供的VPN网络业务中实现新的、离级的报告和控制功链。

关键词：控制功能 VPN 网络业务通信业务运营商

The Global Energy and Water Exchanges(GEWEX)Project in Central Asia:The Case for a Regional Hydroclimate Project

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Advances in Atmospheric Sciences 2024年第5期41卷 777-783页

作者： Michael BRODY Maksim KULIKOV Sagynbek ORUNBAEV Peter j.VAN OEVELEN International Agricultural University Tashkent 111200Uzbekistan george Mason University FairfaxVirginia 22030USA University of Central Asia Bishkek 720001Kyrgyz Republic American University of Central Asia Bishkek 720060Kyrgyz Republic International GEWEX project George Mason UniversityFairfaxVirginia 22030USA

Central Asia consists of the former Soviet Republics,Kazakhstan,Kyrgyz Republic,Tajikistan,Turkmenistan,and *** region’s climate is continental,mostly semi-arid to *** is a significant part of the region’s *** its nature of intensive water use,agriculture is extremely vulnerable to climate *** growth and irrigation development have significantly increased the demand for water in the *** climate change issues include melting glaciers and a shrinking snowpack,which are the foundation of the region’s water resources,and a changing precipitation *** glaciers are located in Kyrgyzstan and Tajikistan,leading to transboundary water resource *** already has extremely high *** indicate that Central Asia has been warming and precipitation might be *** warming is expected to increase,but its spatial and temporal distribution depends upon specific global *** of future precipitation show significant uncertainties in type,amount,and *** Hydroclimate Projects(RHPs)are an approach to studying these *** steps to develop an RHP began in 2021 with a widely distributed online survey about these climate *** was followed up with an online workshop and then,in 2023,an in-person workshop,held in Tashkent,*** for the Global Energy and Water Exchanges(GEWEX)project for the region include both observations and modeling,as well as development of better and additional precipitation observations,all of which are topics for the next workshop.A well-designed RHP should lead to reductions in critical climate uncertainties in policy-relevant timeframes that can influence decisions on necessary investments in climate adaptation.

关键词： GEWEX Central Asia climate change agriculture

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微波辅助有机合成——应用于药物开发

生命科学仪器 2003年第6期1卷 48-50页

作者： Michael j.collins 刘威志 Analytical & Life Sclence System Association

多年来,药物开发的瓶颈一直是在合成这个步骤上,其原因在于用以驱使合成反应的方式一直是传统的热力加热。而最新技术的开发让微波成为加热反应更有效的方法。那些本需要几小时,甚至几天才能完成的合成反应现在只需几分钟,因而让有机化... 详细信息

多年来,药物开发的瓶颈一直是在合成这个步骤上,其原因在于用以驱使合成反应的方式一直是传统的热力加热。而最新技术的开发让微波成为加热反应更有效的方法。那些本需要几小时,甚至几天才能完成的合成反应现在只需几分钟,因而让有机化学家们有更多的时间用以分析和优化他们的反应,使他们更有创造性。微波合成包括很多有优点,例如反应速率的提升,产率的提高和“更干净”的化学。由CEM所开发的新型微波环形单膜腔把所有传统合成设备的优点以及微波瞬间加热的能力结合于一个简洁但具有强大作用的仪器上。Abbott实验室(芝加哥、伊利诺斯)使用此仪器执行了针对药物开发的合成反应。化学家们发现环形单膜腔辅助有机合成的好处是在传统方法和从前的微波方法上的大量改良。

关键词：微波辅助化学有机合成化学药物开发微波加热

DNA-PKcs subunits in radiosensitization by hyperthermia on hepatocellular carcinoma hepG_2 cell line

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World journal of Gastroenterology 2002年第5期8卷 797-803页

作者： Walter j.Curran george Iliakis Department of Radiation Oncology of Kimmel Cancer Center Thomas Jefferson UniversityPhiladelphiaPA 19107USA

AIM: To investigate the role of DNA-PKcs subunits inradiosensitization by hyperthermia on hepatocellularcarcinoma HepG2 cell ***: Hep G2 cells were exposed to hyperthermiaand irradiation. Hyperthermia was given at 45.5 ℃Cellsurvival was determined by an in vitro clonogenic assay forthe cells treated with or without hyperthermia at varioustime points. DNA DSB rejoining was measured usingasymmetric field inversion gel electrophoresis (AFIGE). TheDNA-PKcs activities were measured using DNA-PKcs enzymeassay ***: Hyperthermia can significantly enhanceirradiation-killing cells. Thermal enhancement ratio ascalculated at 10 % survival was 2.02. The difference inradiosensitivity between two treatment modes manifestedas a difference in the α components and the almost sameβ components, which α value was considerably higher inthe cells of combined radiation and hyperthermia ascompared with irradiating cells (1.07 Gy-1 versus 0.44 Gy1). Survival fraction showed 1 logarithm increase after an8-hour interval between heat and irradiation, whereas DNA-PKcs activity did not show any recovery. The cells wereexposed to heat 5 minutes only, DNA-PKcs activity wasinhibited at the nadir, even though the exposure time waslengthened. Whereas the ability of DNA DSB rejoining wasinhibited with the increase of the length of hyperthermictime. The repair kinetics of DNA DSB rejoining aftertreatment with Wortmannin is different from thehyperthermic group due to the striking high slow ***: Determination with the cell extracts andthe peptide phosphorylation assay, DNA-PKcs activity wasinactivated by heat treatment at 45.5 C, and could notrestore. Cell survival is not associated with the DNA-PKcsinactivity after heat. DNA-PKcs is not a unique factor affectingthe DNA DSB repair. This suggests that DNA-PKcs do notplay a crucial role in the enhancement of cellularradiosensitivity by hyperthermia.

关键词：肝癌放射治疗放射敏感性催化作用 DNA激酶

Understanding Performance for Two 802.11 Competing Flows

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journal of Computer Science & Technology 2008年第3期23卷 365-376页

作者： Michael j.Feeley Brendan Cully Sharath j.george Department of Computer Science University of British ColumbiaVanconverCanada

It is well known that 802.11 suffers from both inefficiency and unfairness in the face of competition and interference. This paper provides a detailed analysis of the impact of topology and traffic type on network performance when two flows compete with each other for airspace. We consider both TCP and UDP flows and a comprehensive set of node topologies. We vary these topologies to consider all combinations of the following four node-to-node interactions：（1） nodes unable to read or sense each other, （2） nodes able to sense each other but not able to read each other＇s packets and nodes able to communicate with （3） weak and with （4） strong signal. We evaluate all possible cases through simulation and show that the cases can be reduced to 9 UDP and 10 TCP 802.11g models with similar efficiency/fairness characteristics. We also validate our simulation results with extensive experiments conducted in a laboratory testbed. These more detailed models improve on previous work such as hidden-/exposed-terminal categorization and are thus better suited as a basis for adaptive techniques to improve performance in 802.11 multi-hop WLAN or Mesh Networks.

关键词： 802.11 wireless unfairness two-flow competition network topology