Performance of a large-scale greenhouse solar dryer integrated with phase change material thermal storage system for drying of chili

ABSTRACT

Large-scale greenhouse solar dryers have been used for drying various products and this type of dryer is usually equipped with LPG burner as auxiliary heater, which creates more operating cost. To overcome this problem, phase change material (PCM) thermal storage was proposed to substitute for the LPG burner. In this work, the performance of a large-scale greenhouse solar dryer integrated with a PCM as a latent heat storage for drying of chili was investigated. Experimental studies were conducted to compare the performance of this dryer with that of another large-scale greenhouse solar dryer without the PCM thermal storage and open sun drying. Chili with an initial moisture content of 74.7% (w.b.) was dried to a final moisture content of 10.0% (w.b.) in 2.5 days, 3.5 days, and 11 days using the solar dryer integrated with the PCM thermal storage, the solar dryer without the PCM thermal storage and the open sun drying, respectively. The performance of the solar dryer integrated with the PCM thermal storage was also evaluated using exergy analysis. The exergy efficiency of the drying room of the solar dryer integrated with the PCM thermal storage and the solar dryer without the PCM thermal storage for drying of chili was found to be 13.1% and 11.4%, respectively and the thermal storage helps to dry chili during adverse weather conditions. The results of exergy analysis implied that the exergy losses from the dryer with the PCM should be reduced.     

中国全新世气候变化研究进展

全新世气候变化研究是古气候研究的一个重点。中国全新世气候变化的研究也是全球变化研究中重要的一部分。大量的研究工作为恢复中国全新世气候做了重大贡献。中国地形地貌复杂 ,又处在具有复杂时空变率的东亚季风控制范围内 ,这使得不同的研究工作者在一些问题上存在意见分歧。比较统一的意见是 :中国全新世始于约 10 .5kaBP ;在约 9～ 8kaBP左右为一段降温期 ;7～ 4kaBP为一段温暖期 ,通常称之为全新世大暖期 ;大约 3kaBP左右开始降温 ,至近代才又升温 ;约 130 0aA .D .左右进入小冰期 ,到 185 0aA .D .左右结束 ,其间又有几次比较明显的温度振荡。 185 0aA .D .至今为温度的上升期。对于气候变动的驱动因素 ,不同的学者看法不一 ;从长时间尺度看 ,太阳辐射变化是气候变化的主要驱动力。     

环境样品中PCBs的测定

详细地介绍了应用ＧＣ／ＭＳ或ＧＣ／ＥＣＤ测定样品的ＰＣＢｓ的分析方法及榈前处理的方法，并给出了３０个行政检查样品的测定结果。     

A numerical method for spherical particle motion in turbulent flow with large Reynolds number

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｏｌｉｄ／ｆｌｕｉｄｔｗｏｐｈａｓｅｆｌｏｗｓａｒｅｏｆｔｅｎｅｎｃｏｕｎｔｅｒｅｄｉｎｍａｎｙｅｎｖｉｒｏｎｍｅｎｔａｌ，ｃｈｅｍｉｃａｌａｎｄｈｙｄｒａｕｌｉｃｅｎｇｉｎｅｅｒｉｎｇ，ｓｕｃｈａｓｓｅｄｉｍｅｎｔｔｒａｎｓｐｏｒｔａｔｉｏｎｉｎｒｉｖｅｒｓ，ｗａｓｔｅｗａｔｅｒｆｌｏｗｗｉｔｈｓｏｌｉｄｐａｒｔｉｃｌｅｓａｎｄｓｏｏｎ．Ｒｅｃｅｎｔｌｙ，ｃｏｎｓｉｄｅｒａｂｌｅｅｆｆｏｒｔｓｒｅｇａｒｄｉｎｇｎｕｍｅｒｉｃａｌｐｒｅｄｉｃｔｉｏｎｓｈａｖｅｂ…     

二次颗粒物源成分谱的建立在尘源解析中的作用

通过CMB模型计算各类尘源对TSP、PM10的影响时发现,二次颗粒物对尘源解析起到了不容忽视的作用,因此就二次颗粒物源成分谱进行了专门解析研究,并把二次颗粒物解析也纳入到模型中来,从而完善了源解析结果。     

鼎湖山臭氧、氮氧化物和太阳可见光辐射相互关系的研究

给出了１９９６年了在广东肇庆鼎湖山自然保护区对太阳可见光 段辐射，地面臭氧、ＮＯ、ＮＯ２浓度的观测结果，对影响地面臭氧、ＮＯ、ＮＯ２的主要因子进行了分析，并得到了较好的结果，晴天条件下，地面臭氧浓度、ＮＯ、ＮＯ２浓度有明显的日变化；阴天条件下，地面臭氧浓度、ＮＯ、ＮＯ２浓度的日变化要复杂一些。     

北京地区大气气溶胶的物理特征

对1982年4月在北京沙河利用飞机取得的5份大气气溶胶资料进行综合分析,给出直径0.5—8.0μm气溶皮粒子数浓度和质量浓度的空间分布、谱分布.讨论了逆温、风和湿度等对大气气溶胶粒子的影响.     

利用荧光淬灭作用研究川泽泻凝集素微环境与生色基团的空间分布

用不带电荷的极性淬灭剂丙烯酰胺和带电荷的I-离子、Cs 对川泽泻凝集素内源荧光进行淬灭研究,以揭示凝集素与小分子物质相互作用以及凝集素荧光生色基团的分布情况.天然川泽泻(Alisma plantago-aquatica Linn)凝集素在280nm和295nm波长下均显示λmax为328nm的荧光发射光谱,表明凝集素荧光生色基团位于相对疏水的环境中.中性淬灭剂丙烯酰胺对凝集素分子的荧光生色基团Tyr和Trp残基的可接近程度为96.81%,而对阴离子淬灭剂I-离子和阳离子淬灭剂Cs 离子的可接近程度分别为37.17%和21.96%.表明川泽泻凝集素荧光氨基酸残基主要位于分子内部的疏水核心.图3参22     

品红的深度氧化机理研究

选用 2 5 3 7nm的紫外光为激发光源 ,对品红 /过氧化氢体系中的紫外光解离进行了研究 .结果表明 ,该体系中品红的解离近似为表观一级反应 ,解离反应的速率常数为 0 0 386 7s- 1.品红水溶液的脉冲瞬态光谱结果表明 ,品红主要与OH自由基反应而导致脱色 ,其在 5 4 0nm处的脱色与 34 0nm处的瞬态吸收存在很好的相关性 ,品红在5 4 0nm处脱色为一级反应 ,速率常数为 8 1 0× 1 0 5s- 1,34 0nm处新的瞬态物种生成较快而衰减较慢 ,其衰减速率为 5 33× 1 0 3 s- 1.     

Governing the termination problem in solar radiation management

ABSTRACT

Technologies for Solar Radiation Management (SRM) could limit global warming by manipulating the Earth’s radiation balance. A major objection to SRM is the termination problem: the catastrophic consequences that are likely to result from its sudden discontinuation. The termination problem limits the reversibility of policy choices and poses the risk of inadvertent or enforced program collapse. It is often considered a major impediment to the governability of SRM. In a first attempt to systematically engage with the question of institutional design for resolving the termination problem, the scenarios in which the termination problem arises as well as their respective drivers are identified. Scenarios and drivers are then used to derive institutional solutions in the form of excludable benefits, scientific oversight and phase-out mechanisms. While other objections to SRM may remain valid, it is concluded that the termination problem raises fewer challenges for international governance than is usually assumed.