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Evaluation of the feeding value of two tropical cereal straws, maize stover, rice straw and their botanical fractions by nylon and mobile bag technique 用尼龙和流动袋技术评价两种热带谷物秸秆、玉米秸秆、水稻秸秆及其植物组分的饲用价值
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I1.44642
D. M. Mgheni, E. Ndemanisho, T. Hvelplund, Weisbjerg
Degradability characteristics of dry matter (DM), protein free DM (PFDM) and nitrogen (N) were estimated in maize stover, rice straw and their botanical fractions using the nylon bag technique. True intestinal digestibility of the intact feed protein (TID) was also estimated using the mobile bag technique. The results indicated that cereal straws and their botanical fractions have substantial variation in the extent and rate at which DM, PFDM and N were degraded in the rumen. The protein values of Total amino acid absorbed from the small intestine (AAT) , Protein balance in the rumen (PB) and TID ranged from 49 to 81 g kg-1DM, in PBV from –89 to – 61 g kg-1 DM and TID of 34 to 69 percent DM in both straws and their botanical fractions. The predicted dry matter intake (DMI) value for whole maize stover was slightly higher (5.2 kg DM d-1) than whole rice straw (4.9 kg DM d-1). High variations (4.5 to 6.1 kg DM d-1 for maize stover and 4.5 to 5.7 kg DM d-1 for rice straw) were observed within the two cereal straw botanical fractions. It was concluded that the two cereal straws are of very low feeding value and to increase their production potential improvement method strategies like chemical treatment and/or supplementation are inevitable.
采用尼龙袋技术测定了玉米秸秆、水稻秸秆及其植物组分中干物质(DM)、无蛋白DM (PFDM)和氮(N)的降解特性。利用移动袋技术估计完整饲料蛋白的肠道真消化率。结果表明,谷物秸秆及其植物组分在瘤胃中降解DM、PFDM和N的程度和速率存在较大差异。秸秆及其植物组分的总氨基酸吸收(AAT)、瘤胃蛋白质平衡(PB)和TID值为49 ~ 81 g kg-1DM, PBV值为- 89 ~ - 61 g kg-1DM, TID值为34% ~ 69% DM。全株玉米秸秆的干物质采食量(DMI)预测值(5.2 kg DM -1)略高于全株水稻秸秆(4.9 kg DM -1)。两种谷物秸秆植物组分之间存在较大差异(玉米秸秆为4.5 ~ 6.1 kg DM -1,水稻秸秆为4.5 ~ 5.7 kg DM -1)。综上所述,这两种谷物秸秆的饲用价值很低,为了提高其生产潜力,必须采取化学处理和/或补充等改进措施。
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引用次数: 4
Non-square quantum well growth for reduced threshold current in tensilely strained lasers operating at 1.52m 工作在1.52m的张应变激光器中降低阈值电流的非平方量子阱生长
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I1.44630
K. Kaduki
This paper presents calculations demonstrating that non-square quantum well growth (well shaping) can result in reduced threshold current for tensilely strained quantum well bipolar diode lasers operating at 1.52im m. Calculations of subband structure, optical matrix elements and laser gain are performed for arbitrarily shaped quantum wells based on a 4-band (electron/heavyhole/ light-hole/split off-hole) Hamiltonian. For long wavelength (1.3im m to 1.55im) lasers, Auger recombination dominates the threshold current. Compared to a 1.52 mm optimal square well just below critical thickness, an InGaAs-InGaAsP (on InP) well incorporating potential ‘spikes’ and having the same wavelength can be much wider. The wider well, possible with well shaping, results in a lower value for three-dimensional (3D) carrier density at a given value of modal gain. For low loss lasers, this implies a reduction in Auger (and hence total) threshold current to a value below the best obtainable in a laser based on a square quantum well.
本文给出了计算结果,证明非平方量子阱生长(阱整形)可以降低工作在1.52 m的张力应变量子阱双极二极管激光器的阈值电流。基于4波段(电子/重空穴/光空穴/分裂离空穴)哈密顿量,计算了任意形状量子阱的子带结构、光学矩阵元素和激光增益。对于长波长(1.3 m ~ 1.55 m)激光,俄歇复合主导着阈值电流。与刚好低于临界厚度1.52 mm的最佳方形井相比,InGaAs-InGaAsP(在InP上)井具有潜在的“尖峰”并且具有相同的波长,可以更宽。在给定的模态增益值下,更宽的井(可能采用井形)会导致更低的三维载流子密度值。对于低损耗激光器,这意味着俄歇(因此总)阈值电流降低到低于基于方形量子阱的激光器中可获得的最佳值。
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引用次数: 1
THIN- LAYER DRYING OF DICED CASSAVA ROOTS 切片木薯根的薄层干燥
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I2.44677
S. Kajuna, V. Silayo, A. Mkenda, P. Makungu
Fresh cassava (Manihot spp) roots were obtained from a farm and used in this study. They were peeled and diced using a special dicing machine into cubes of side 0.5 cm. The cubes were dried in thin layers (one to three layers) in a drier that was specifically designed and fabricated in the Department of Agricultural Engineering and Land Planning, Morogoro, Tanzania for the purpose. The drier had a motor driven fan, a heater and a tray chamber, with thermometers for determining entry and exit temperature (dry and wet bulb) conditions of the air. The input variables were: depth of thin layer (0.5, 1.0 and 1.5 cm), drying temperature of the air (55 and 65 oC) and drying time (from 0 min until the sample attained equilibrium, at intervals of 25 min). The response variable was the moisture content of the cassava cubes. Weather conditions during the experiments were also monitored. A parallel sun drying experiment was carried out to compare thin layer drying on the sun and thin layer drying in the fabricated dryer. For the fresh cassava that was used in the experiments, a duplicate sample was placed in an oven at 75 oC for 7 hours to determine the initial moisture content. The results indicated that the average moisture content of fresh cassava roots was about 75.4 %(w.b.). Both temperature and depth of layers were found to affect the drying characteristics of cassava cubes, with single layer and higher drying temperature giving faster approaches to equilibrium moisture content. Comparing sun drying of one layer at an average temperature of 25 oC with artificial drying at the above named temperatures, it was found that sun drying took 2 to 3 days to reduce the moisture content to Equilibrium Moisture Content (EMC), while this was achieved within 150 min and 125 min with artificial drying at 55 oC and 65 oC respectively. The generally accepted thin layer drying equations were fitted to the drying data of cassava cubes, and the Page model was found to agree with the drying data of one, two and three layers with high accuracy for artifial drying, but not for sundrying. The exponential model only agreed accurately with drying of one layer.
新鲜木薯根(Manihot spp)从一个农场获得并用于本研究。用一种特殊的切丁机把它们削皮切成边长0.5厘米的立方体。在坦桑尼亚莫罗戈罗农业工程和土地规划部为此目的专门设计和制造的干燥机中,将立方体干燥成薄薄的一层(一到三层)。干燥机有一个电机驱动的风扇,一个加热器和一个托盘室,配有温度计,用于确定空气的入口和出口温度(干球和湿球)条件。输入变量为:薄层深度(0.5,1.0和1.5 cm),空气干燥温度(55和65℃)和干燥时间(从0分钟到样品达到平衡,间隔25分钟)。响应变量为木薯块的含水量。实验期间的天气状况也进行了监测。进行了平行日光干燥试验,比较了制备的干燥器在日光下的薄层干燥和在干燥器内的薄层干燥。对于实验中使用的新鲜木薯,将一个重复的样品放在75℃的烤箱中7小时,以确定初始水分含量。结果表明,新鲜木薯根的平均含水量约为75.4% (w.b.)。温度和层深都影响木薯块的干燥特性,单层和较高的干燥温度可以更快地达到平衡水分含量。将平均温度为25℃的单层日光干燥与上述温度下的人工干燥进行比较,发现日光干燥需要2 ~ 3 d才能将水分含量降低到平衡水分含量(EMC),而在55℃和65℃的人工干燥分别需要150 min和125 min。将普遍接受的薄层干燥方程拟合到木薯立方体的干燥数据中,发现Page模型与人工干燥的一层、二层和三层的干燥数据吻合,精度较高,但不适合晒干。指数模型只准确地反映了一层的干燥情况。
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引用次数: 44
REACTIONS OF O-AMINO-N-(1,1-DIMETHYLPROP-2-YNYL)-BENZAMIDE 邻氨基- n -(1,1-二甲基丙基-2-炔基)-苯酰胺的反应
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I1.44638
C. Usifoh, L. Okunrobo
Carbonylation of o-amino-N-(1,1-dimethylprop-2-ynyl)-benzamide 3 with ethyl chloroformate gave 2-carbethoxyamino-N-(1,1-dimethylprop- 2-ynyl)-benzamide 6. Attempted cyclization of 6 under basic conditions did not give the quinazoline 8 but an oxazole 7. When 3 was also refluxed in triethylorthoformate-acetic anhydride mixture, 2-acetylamino-N-(1,1-dimethylprop- 2-ynyl)-benza-mide 4 was formed as the major compound with negligible amount of 3-(1,1- dimethylprop-2-ynyl)-quinazolin-4-(3H)-one 5.
邻氨基- n -(1,1-二甲基丙-2-炔基)-苯酰胺3与氯甲酸乙酯羰基化得到2-碳氧基氨基- n -(1,1-二甲基丙-2-炔基)-苯酰胺6。在基本条件下对6进行环化,得到的不是喹唑啉8,而是恶唑7。当3也在三乙基甲甲酸乙酯-乙酸酐混合物中回流时,形成2-乙酰氨基- n-(1,1-二甲基丙-2-炔基)-苯甲酰胺4作为主要化合物,3-(1,1-二甲基丙-2-炔基)-喹唑啉-4-(3H)- 1- 5的量可忽略。
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引用次数: 0
Lathe stability charts via acoustic emission monitoring 通过声发射监测车床稳定性图表
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I2.44675
J. Keraita, Hj Oyango, G. K. Misoi
Signal parameters characterizing acoustic emission (AE) detected during metal cutting have been theoretically correlated in a simple manner, to the work material properties, cutting conditions, and tool geometry. During chatter, the cutting conditions and the tool geometry change considerably. Self-exited chatter, an instability of the cutting process in combination with the machine structure, is a basic performance limitation of machine tools. In the research findings presented in this paper, changes occurring to AE signal parameters have been used to detect the onset of chatter and hence plot stability charts, during a turning operation. Apart from showing the borderlines of stability, such charts can be used to identify the necessary changes required to eliminate chatter at minimum or no loss of production. The signal parameters investigated include AE mean intensity level, the skew and kurtosis of the power spectrum; as well as the count rate of the emissions.
表征金属切削过程中检测到的声发射(AE)的信号参数在理论上以一种简单的方式与工作材料特性、切削条件和刀具几何形状相关联。在颤振过程中,切削条件和刀具几何形状发生了很大的变化。自激颤振是切削加工过程中与机床结构结合产生的一种不稳定性,是机床性能的一个基本限制。在本文提出的研究成果中,AE信号参数的变化被用来检测颤振的开始,从而绘制稳定性图,在转向操作期间。除了显示稳定性的边界外,这种图表还可以用来确定在最小限度或不损失生产的情况下消除颤振所需的必要变化。研究的信号参数包括声发射平均强度、功率谱的偏度和峰度;以及排放的计数率。
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引用次数: 8
Elements de precision sur la systematique d’especes adventices dugenre corchorus l. (tiliaceae) au Senegal 塞内加尔corchorus l. (tiliaceae)属杂草系统的精确元素
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I1.44639
Mbaye, K. Noba, R. Sarr, A. Kane, Jm Sambou, B. Tidiane
Corchorus L is a genus includes nearly 40 species widelydistributed throughout the tropics and is represented in Senegal by 5 species according to Berhaut : C. aestuans L.; C. fascicularis Lam., C. olitorius L. with 2 varieties C. olitorius var olitorius L. and C. olitorius var incisifolius Asch. & Schw; C. tridens L. and C. trilocularis L.. Interest for these species is both economic and systematic. Indeed, beyond their weed statute and because of their ethnobotanical properties some species are cultivated. Besides, in the botanical point of view they belong to a genus which is a transition group between two tribes ; Tiliae and Grewiae. Even works done on the genus, identification of these species is still difficult. In fact, the more discriminant characters put ahead concern those of the fruit, an organ which appears late in the plant life cycle. Investigations on vegetative and reproductive organs on adult plant showed that, the presence or absence of basal hair on the limb, the dentate or lacerate leaves, the ovary 3 or 5-celled, the circular or hexagonal or pentagonal or trigonal secttion of the fruit, the seeds contiguous or separate inside the fruit are additional characters which could better help to identify these species.
Corchorus L是一个属,包括近40种,广泛分布于整个热带地区,根据Berhaut,在塞内加尔有5种:C. aestuans L.;花束草,有2个品种,分别为:山茱萸变种、山茱萸变种、山茱萸变种。&等;三叶草和三叶草。对这些物种的兴趣既是经济上的,也是系统上的。事实上,除了杂草法规之外,由于它们的民族植物学特性,一些物种被种植。此外,从植物学的观点来看,它们属于一个属,是两个部落之间的过渡群;tilae和Grewiae。即使对属进行了研究,鉴定这些物种仍然很困难。事实上,前面提出的更具区别性的性状与果实有关,果实是植物生命周期中较晚出现的器官。对成虫的营养器官和生殖器官的调查表明,残肢上是否有基毛、叶片是否有齿状或撕裂状、子房是否有3或5细胞、果实的圆形或六角形或五角形切片、种子是否在果实内连续或分离,这些特征都能很好地帮助鉴定这些物种。
{"title":"Elements de precision sur la systematique d’especes adventices dugenre corchorus l. (tiliaceae) au Senegal","authors":"Mbaye, K. Noba, R. Sarr, A. Kane, Jm Sambou, B. Tidiane","doi":"10.4314/AJST.V2I1.44639","DOIUrl":"https://doi.org/10.4314/AJST.V2I1.44639","url":null,"abstract":"Corchorus L is a genus includes nearly 40 species widelydistributed throughout the tropics and is represented in Senegal by 5 species according to Berhaut : C. aestuans L.; C. fascicularis Lam., C. olitorius L. with 2 varieties C. olitorius var olitorius L. and C. olitorius var incisifolius Asch. & Schw; C. tridens L. and C. trilocularis L.. Interest for these species is both economic and systematic. Indeed, beyond their weed statute and because of their ethnobotanical properties some species are cultivated. Besides, in the botanical point of view they belong to a genus which is a transition group between two tribes ; Tiliae and Grewiae. Even works done on the genus, identification of these species is still difficult. In fact, the more discriminant characters put ahead concern those of the fruit, an organ which appears late in the plant life cycle. Investigations on vegetative and reproductive organs on adult plant showed that, the presence or absence of basal hair on the limb, the dentate or lacerate leaves, the ovary 3 or 5-celled, the circular or hexagonal or pentagonal or trigonal secttion of the fruit, the seeds contiguous or separate inside the fruit are additional characters which could better help to identify these species.","PeriodicalId":7641,"journal":{"name":"African Journal of Science and Technology","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84189492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 11
A CUTTING- PLANE APPROACH FOR SEMI- INFINITE MATHEMATICAL PROGRAMMING 半无限数学规划的切割平面方法
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I1.44628
M. Luhandjula, M. Ouanes
Many situations ranging from industrial to social via economic and environmental problems may be cast into a Semi-infinite mathematical program. In this paper, the cutting-plane approach which lends itself better for standard non-linear programs is exploited with good reasons for grappling with linear, convex and geometric Semi-infinite programs. For each case, computational aspects are discussed and convergence statements established. Simple numerical examples are also provided for the sake of illustration. The paper ends by briefly comparing the cutting-plane approach discussed here with other existing approaches and by stressing the necessity of pushing forward a Decision Support System effectively capable for helping someone faced with a problem that can be formulated as a Semi-infinite mathematical program.
许多情况,从工业到社会,再到经济和环境问题,都可以用半无限数学程序来描述。在本文中,切割平面方法更适合于标准非线性规划,并有充分的理由用于处理线性、凸和几何半无限规划。对于每种情况,讨论了计算方面并建立了收敛性陈述。为了说明问题,还提供了简单的数值例子。本文最后简要地比较了这里讨论的切面方法与其他现有方法,并强调了推动一个决策支持系统的必要性,该系统能够有效地帮助人们面对可以被表述为半无限数学规划的问题。
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引用次数: 1
EFFETS DE L'EXTRAIT AU CYCLOHEXANE DE BIDENS PILOSA L. (ASTERACEAE) SUR LA MOTRICITE INTESTINALE DE RAT 菊科环己烷提取物对大鼠肠道运动能力的影响
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I1.44632
D. Thiophile, A. Rakotonirina, R. Kamgang, Tr Tankwa, K. Wanda, G. Magloire
Effects of cyclohexane extract of Bidens pilosa L. on rat intestinal motility. – In vitro, we have studied the effects of the cyclohexane extract of Bidens pilosa leaves (B.p.) on the rat ileum smooth muscle motility. B.p. has showed dose-dependent stimulators effects on both tonicity and amplitude of the spontaneous contractions. With 160 ig/mL of extract maximal stimulation was obtained. With that dose, the rate of variation was 1027 %. Atropine reduced by 77 % the spasmogenic effects of B.p. and by 94 % the acetylcholine effects. In Ca2+ free solution, stimulation contraction by 160 ig/mL of the extract was reduced to 400 %, while Nifedipine completely inhibited the spasmogenic effects of the extract. These results suggest that the cyclohexane extract of B.p. could stimulate ileal smooth muscle contractions through muscarinic receptors which increase Ca2+ mobilization from both extra- and intracellular milieu.
菟丝子环己烷提取物对大鼠肠道蠕动的影响。在体外,我们研究了毛拜登叶环己烷提取物(B.p.)对大鼠回肠平滑肌运动的影响。bp对自发性收缩的张力和幅度均有剂量依赖性刺激作用。当提取液浓度为160 ig/mL时,刺激最大。在该剂量下,变异率为1027%。阿托品减少了77%的B.p.痉挛作用和94%的乙酰胆碱作用。在无Ca2+溶液中,160 ig/mL的刺激收缩减少到400%,而硝苯地平完全抑制了提取物的致痉挛作用。这些结果表明,B.p.环己烷提取物可以通过毒蕈碱受体刺激回肠平滑肌收缩,从而增加细胞外和细胞内Ca2+的动员。
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引用次数: 4
MACROPHYTES ET GROUPEMENTS VÉGÉTAUX AQUATIQUES ET AMPHIBIES DE LA BASSE VALLÉE DU FERLO (SÉNÉGAL) FERLO山谷下游的大型植物、水生植物和两栖植物群(塞内加尔)
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I1.44651
A. Sarr, A. Thiam, A. Bâ
The reflooding of the Ferlo Valley since 1988 after 32 years of drying up has caused progressive growth of aquatic plants. 103 woody and herbaceous plants falling into 81 genera and 38 families were identified in the Valley. Analysis of the vegetation using the transect technique and the Braun Blanquet method helped to establish the floristic composition of 7 aquatic and semi aquatic plants groups. Typha domingensis and Pistia stratiotes are dominant in the aquatic miieu whereas Tamarix senegalensis plant groups were frequently found in the flood plain, indicating that the tidal range is important and soil salinity was still high.
经过32年的干旱,费罗河谷从1988年开始重新泛滥,导致水生植物逐渐生长。共鉴定出木本和草本植物103种,隶属于38科81属。利用样带技术和Braun Blanquet方法对植被进行分析,确定了7个水生和半水生植物类群的区系组成。水栖环境中以霸王台风(Typha domingensis)和层状雌鱼(Pistia stratiotes)为主,而冲积平原中则多见塞内加尔柽柳(Tamarix senegalensis)植物群,说明潮差的重要性和土壤盐度仍然较高。
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引用次数: 7
EU/Th AND 14 C isotope dating of lake sediments from sacred lake and lake Nkunga, Kenya 肯尼亚圣湖和恩孔加湖湖泊沉积物EU/Th和14c同位素定年
Pub Date : 2009-07-28 DOI: 10.4314/AJST.V2I1.44633
D. Olago, F. Street-Perrott, R. Perrott, M. Ivanovich, D. Harkness
In the tropical regions, lake and swamp sediment core chronologies have traditionally been established solely by radiocarbon dating. In several instances, however, the radiocarbon sampling resolution has been coarse, entailing extrapolations over time periods where there may have been considerable change in sedimentation rates related, for example, to significant, albeit abrupt, palaeoclimatic and palaeoenvironmental change. Moreover, some cores may age-wise exceed the radiocarbon dating limit of ca.40,000 yr, thus entailing tenuous extrapolations of radiocarbon dates obtained in the younger sections of the core in order to obtain a whole core chronology. In this paper, the chronology of lake sediment cores retrieved from Sacred Lake and Lake Nkunga on the north-eastern flank of Mount Kenya is established using a combination of highresolution radiocarbon dating and experimental U/Th dating to circumvent the drawbacks mentioned above. The derived chronosequences, which show that these sediment records span almost the whole of the late Quaternary period, demonstrate the efficacy and synergism of these dating techniques.
在热带地区,湖泊和沼泽沉积物岩心年代学传统上仅通过放射性碳定年法确定。然而,在若干情况下,放射性碳取样的分辨率是粗糙的,需要在沉积物速率可能发生相当大变化的时期内进行外推,例如,与显著的、尽管是突然的古气候和古环境变化有关。此外,一些岩心的年龄可能超过了约40,000年的放射性碳定年限制,因此需要对岩心较年轻部分获得的放射性碳定年进行微弱的外推,以获得整个岩心年代学。本文采用高分辨率放射性碳测年和实验U/Th测年相结合的方法,建立了肯尼亚山东北侧圣湖和恩孔加湖沉积物岩心年代学,克服了上述缺点。这些沉积记录几乎跨越了整个晚第四纪,证明了这些测年技术的有效性和协同作用。
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引用次数: 4
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African Journal of Science and Technology
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