Analysis of Solar Direct-Driven Organic Rankine Cycle Powered Vapor Compression Cooling System Combined with Electric Motor for Office Building Air-Conditioning

Solar energy powered organic Rankine cycle vapor compression cycle(ORC-VCC)is a good alternative to convert solar heat into a cooling effect.In this study,an ORC-VCC system driven by solar energy combined with electric motor is proposed to ensure smooth operation under the conditions that solar radiation is unstable and discontinuous,and an office building located in Guangzhou,China is selected as a case study.The results show that beam solar radiation and generation temperature have considerable effects on the system performance.There is an optimal generation temperature at which the system achieves optimum performance.Also,as a key indicator,the cooling power per square meter collector should be considered in the hybrid solar cooling system in design process.Compared to the vapor compression cooling system,the hybrid cooling system can save almost 68.23%of electricity consumption.

Fractal Image Compression Using Self-Organizing Mapping

One of the main disadvantages of fractal image data compression is a loss time in the process of image compression (encoding) and conversion into a system of iterated functions (IFS). In this paper, the idea of the inverse problem of fixed point is introduced. This inverse problem is based on collage theorem which is the cornerstone of the mathematical idea of fractal image compression. Then this idea is applied by iterated function system, iterative system functions and grayscale iterated function system down to general transformation. Mathematical formulation form is also provided on the digital image space, which deals with the computer. Next, this process has been revised to reduce the time required for image compression by excluding some parts of the image that have a specific milestone. The neural network algorithms have been applied on the process of compression (encryption). The experimental results are presented and the performance of the proposed algorithm is discussed. Finally, the comparison between filtered ranges method and self-organizing method is introduced.

Improve Fractal Compression Encoding Speed Using Feature Extraction and Self-organization Network

Image compression consists of two main parts: encoding and decoding. One of the important problems of the fractal theory is the long encoding implementation time, which hindered the acceptance of fractal image compression as a practical method. The long encoding time results from the need to perform a large number of domain-range matches, the total encoding time is the product of the number of matches and the time to perform each match. In order to improve encoding speed, a hybrid method combining features extraction and self-organization network has been provided, which is based on the feature extraction approach the comparison pixels by pixels between the feature of range blocks and domains blocks. The efficiency of the new method was been proved by examples.

Performance comparison and analysis of a combined power and cooling system based on organic Rankine cycle

A novel power and cooling system combined system which coupled organic Rankine cycle(ORC) with vapor compression refrigeration cycle(VCRC) was proposed. R245 fa and butane were selected as the working fluid for the power and refrigeration cycle, respectively. A performance comparison and analysis for the combined system was presented. The results show that dual-pressure ORC-VCRC system can achieve an increase of 7.1% in thermal efficiency and 6.7% in exergy efficiency than that of basic ORC-VCRC. Intermediate pressure is a key parameter to both net power and exergy efficiency of dual-pressure ORC-VCRC system. Combined system can produce maximum net power and exergy efficiency at 0.85 MPa for intermediate pressure and 2.4 MPa for high pressure, respectively. However, superheated temperature at expander inlet has little impact on the two indicators. It can achieve higher overall COP, net power and exergy efficiency at smaller difference between condensation temperature and evaporation temperature of VCRC.

Assessment of strength development in cement-admixed artificial organic soil with GX07

To explore the stabilization effect of stabilizing agent GX07 on treating organic soil and the influence of organic matter on the strength development of stabilized soil,artificial organic soil with various organic matter content was obtained by adding different amounts of fulvic acid into non-organic clay,and then liquid-plastic limit tests were carried out on the artificial organic soil.Meanwhile,unconfined compressive strength(UCS) tests were performed on cement-only soil and composite stabilized soil,respectively.The test results indicate that the plastic limit of soil samples increases linearly,and the liquid limit increases exponentially as the organic matter content increases.The strength of stabilized soil is well correlated with the organic matter content,cement content,stabilizing agent content and curing time.When the organic matter content is 6%,as the cement content varies in the range of 10%-20%,the strength of cement-only soil increases from 88.5 to 280.8 kPa.Once 12.6% GX07 is added into the mix,the strength of stabilized soil is 4.93 times compared with that of cement-only soil.GX07 can obviously improve the strength of cemented-soil and has a good economic applicability.A strength model is proposed to predict strength development.

Effect of Organic Waste on Crystal Structure and Mechanical Properties of Concrete

The influence of organic waste as an additive to concrete formulation has been studied by replacing up to 10% of cement ratio with locally sourced organic additive. The reference cement used was Portland cement;three different organic wastes were used in the mixture: periwinkle shell, extracted silica from corn hob ash and coconut shell ash. Uniform distribution of the additive was ensured by thorough mixing prior to water addition. Casting and curing of the concrete were done in line with established standard. The compressive strength test was carried out using the Instron universal testing machine and the oxides of elemental composition of the cement and the additives were determined using EDXRF Spectrometer (EDX 3600B) while the crystallography studies were carried out using EMMA) X-ray diffractometer . The result obtained indicated that there was a significant difference between the value of density, packing efficiency and compressive strength of each reinforced concrete with that of the reference cement which was attributable to the presence of additives. The cement formulation with silica as admixture was found to have the highest compressive strength of 217.94 MPa, while the reference cement had the lowest compressive strength of 81.45 MPa. This study has established that locally sourced organic additives (emerging additives), influence the mechanical properties of concretes.

Metastatic Spinal Cord Compression (MSCC) —The Evolving Story from Kashmir

Aim: To know the demographics of the patients most commonly involved by metastatic cord compression in Kashmir and to find the commonest primary organ to metastasize to spine causing cord compression. Methods: A hospital-based 10-year retro-prospective study was carried out in the Department of Neurosurgery of Sher-i-Kashmir Institute of Medical Sciences, Soura from July 2002 to June 2012, which is the premier tertiary care institute of the Kashmir valley. Patients were evaluated for metastatic spinal cord compression based on a standard proforma and specialized investigations were carried out and were deemed necessary by the concerned neurosurgical unit. Results: The commonest primary malignancy to metastasize to the spinal column in our study was Non-Hodgkin’s lymphoma, followed in turn by metastatic squamous cell carcinoma lung, metastatic intraductal carcinoma breast and metastatic adenocarcinoma prostate. Predominantly dorsal spine was the commonest region of spine involved by MSCC. Conclusion: Metastatic spinal cord compression is coming up in a big way. As the long-term cancer survivors increase due to multi-modality treatment protocols aimed at treating cancers and prolonging survival, there will be a proportionate increase in the number of patients who will potentially land up in metastatic spinal cord compression.

Compressive and tensile strength of polymer-based fiber composite sand

Traditional soil additives like Portland cement and lime are prone to cause the brittle fracture behavior of soil,and possibly,environmental impacts.This study explores the potential use of polyurethane organic polymer and sisal fiber in improving the mechanical performance of sand.The effects of polymer content,fiber content,and dry density on the unconfined compressive strength(UCS)and direct tensile strength(DTS)of the polymer-fiber-sand composite were evaluated.The results showed significant increase in UCS and DTS of the reinforced sand with the increase of polymer content,fiber content,and dry density.At high dry density condition,a single peaked stress−strain curve is often observed.Higher polymer content is beneficial to increasing the peak stress,while higher fiber content contributes more to the post-peak stress.The combined use of polymers and fibers in soil reinforcement effectively prevents the propagation and development of cracks under the stress.Scanning electron microscopy(SEM)test was also performed to investigate the micro-structural changes and inter-particle relations.It was found through SEM images that the surface coating,bonding,and filling effects conferred by polymer matrix greatly enhance the interfacial interactions,and hence provide a cohesive environment where the strength of fibers could be readily mobilized.

Effects of Sand Quality on Compressive Strength of Concrete: A Case of Nairobi County and Its Environs, Kenya

Failure of concrete structures leading to collapse of buildings has initiated various researches on the quality of construction materials. Collapse of buildings resulting to injuries, loss of lives and investments has been largely attributed to use of poor quality concrete ingredients. Information on the effect of silt and clay content and organic impurities present in building sand being supplied in Nairobi County and its environs as well as their effect to the compressive strength of concrete was lacking. The objective of this research was to establish level of silt, clay and organic impurities present in building sand and its effect on compressive strength of concrete. This paper presents the findings on the quality of building sand as sourced from eight supply points in Nairobi County and its environs and the effects of these sand impurities to the compressive strength of concrete. 27 sand samples were tested for silt and clay contents and organic impurities in accordance with BS 882 and ASTM C40 respectively after which 13 sand samples with varying level of impurities were selected for casting of concrete cubes. 150 mm × 150 mm × 150 mm concrete cubes were cast using concrete mix of 1:1.5:3:0.57 (cement:sand:coarse aggregates:water) and were tested for compressive strength at the age of 7, 14 and 28 days. The investigation used cement, coarse aggregates (crushed stones) and water of similar characteristics while sand used had varying levels of impurities and particle shapes and texture. The results of the investigations showed that 86.2% of the sand samples tested exceeded the allowable limit of silt and clay content while 77% exceeded the organic content limit. The level of silt and clay content ranged from 42% to 3.3% for while organic impurities ranged from 0.029 to 0.738 photometric ohms for the unwashed sand samples. With regard to compressive strength, 38% of the concrete cubes made from sand with varying sand impurities failed to meet the design strength of 25 Mpa at the age of 28 days. A combined regression equation of with R2 = 0.444 was generated predicting compressive strength varying levels of silt and clay impurities (SCI), and organic impurities (ORG) in sand. This implies that 44% of concrete’s compressive strength is contributed by combination of silt and clay content and organic impurities in sand. Other factors such as particle shapes, texture, workability and mode of sand formation also play a key role in determination of concrete strength. It is concluded that sand found in Nairobi County and its environs contain silt and clay content and organic impurities that exceed the allowable limits and these impurities result in significant reduction in concrete’s compressive strength. It is recommended that the concrete design mix should always consider the strength reduction due to presence of these impurities to ensure that target strength of the resultant concrete is achieved. Formulation of policies governing monitoring of quality of building sand in Kenya and other developed countries is recommended.

有机模板孔径和烧结温度对SiC泡沫陶瓷结构和性能影响

SiC泡沫陶瓷作为一种新型多孔材料,因其强度高、硬度高、耐腐蚀、耐高温等优异性能,被广泛应用于冶金、石油化工、航空航天、生物医学等领域。以SiC为主要原料,Al_(2)O_(3)为烧结助剂,采用有机模板浸渍法制备了SiC泡沫陶瓷,研究了有机模板孔径和烧结温度对SiC泡沫陶瓷宏微观形貌、相组成、孔隙率及压缩性能的影响。结果表明:随着有机模板孔径由35 ppi增至20 ppi,SiC泡沫陶瓷的孔隙率由48.3%升至75.6%,而抗压强度由1.94 MPa降至0.40 MPa。随着烧结温度由1350℃提高至1500℃,SiC泡沫陶瓷的孔隙率由78.7%降至68.3%,抗压强度先升后降。在1450℃制备的SiC泡沫陶瓷样品抗压强度最高(1.45 MPa),其孔隙率为71.6%,孔结构完整、颗粒堆积紧密,针眼孔洞、裂纹以及脆性方石英相较少。

有机醇胺TEA-M-无机盐体系对固硫灰渣活性激发的影响

固硫灰渣的处理以及环保型激发剂材料的开发是防止环境二次污染的有效途径。本文开发了一种有机醇胺TEA-无机激发剂M-无机盐复合激发剂,通过SEM、FTIR、XRD等测试方法对所制备的复合激发剂进行表征,先后探索了M、TEA-M、TEA-M-无机盐三个系列的激发剂对水泥胶砂流动度比和抗压活性指数的影响。结果表明,TEA的助磨作用改善了颗粒的粒径,无机激发剂M能影响参与水化反应的Ca(OH)_(2)含量,无机盐CaSiO_(3)后期会产生C-S-H并提供碱性条件。复合激发剂中的不同材料间的协同作用使水泥胶砂7和28 d的抗压活性指数分别提高了29个和18个百分点(与空白样相比),并且胶砂净浆的流动度比仍然保持在较高水平。本文为固硫灰渣提供了一种环保型的复合激发剂材料,促进了固硫灰渣的绿色化应用。

考虑有机质赋存形态的含有机质土一维压缩与渗透特性研究

有机质在土壤中常以不同形态赋存,结合态和自由态是其主要类型,2种赋存形态有机质理化性质有较大差异。但一直以来,土力学领域主要关注有机质含量对土宏观工程性质的影响,有机质赋存形态方面鲜有报道。文章通过人工调配不同有机质含量土样,并基于傅积平法测试土样中不同赋存形态有机质的含量;利用改装的一维固结-渗透仪和常规一维固结仪对相同初始孔隙比e_(0)、不同有机质含量w_(u)土样进行一维渗压和蠕变试验,以期在明确压缩、蠕变及渗透性相关参数随有机质含量变化规律的同时,也厘清有机质赋存形态与上述指标的关联;最后基于压汞(MIP)试验结果,分析不同w_(u)土样在相同初始孔隙比(e_(0)=1.5)以及分级加载下的孔隙特征演变规律。试验结果表明:(1)压缩指数C_(c)总体呈现随w_(u)增大而增大的趋势,但C_(c)-w_(u)关系并非单调而是分段线性关系,分段点对应的w_(u)接近阈值w_(u), 2;次固结系数Ca与w_(u)呈单调线性增大关系。表明有机质赋存形态对C_(c)-w_(u)关系有一定影响,但对Ca-w_(u)关系影响不明显。(2)初始渗透系数kv0随w_(u)增大而减小,减小过程也可分为2个阶段,有机质赋存形态对kv0-w_(u)关系有影响;渗透指数Ck与w_(u)呈线性正相关关系,和有机质赋存形态无明显关联;(3)从MIP结果可知,对于相同e_(0)(=1.5)土样,w_(u)越大,其累积进汞体积减小,封闭型孔隙占比增多,PSD曲线从孔径分散的不规则型向孔径集中的单峰型转变;分级加载下,含结合态有机质为主的土样(w_(u)=4%)与含自由态有机质的土样(w_(u)=20%),二者PSD曲线演变过程不同。

利用ORC-VCR回收压缩热的预冷式CAES系统性能分析

常规非绝热压缩空气储能(D-CAES)系统的储能过程通常采用四级以上的压缩机组以减少空气压缩功的消耗,导致产生大量的低品位压缩热直接排放到环境中,能源浪费严重。针对这一问题,本工作提出了一种采用有机朗肯循环-蒸汽压缩制冷(ORC-VCR)回收压缩热的预冷式CAES系统(ORC-VCR-CAES),通过回收空气压缩阶段压缩机产生的压缩热来对压缩机入口空气进行预冷,可以进一步降低空气压缩功的消耗,提高系统的循环效率。对ORC-VCR-CAES耦合系统进行了热力学分析和经济性分析。结果表明,不同ORC-VCR循环工质对系统性能的影响较大,采用R152a作为循环工质的ORC-VCR-CAES系统综合性能最佳。其系统循环效率可达64.15%,比常规D-CAES系统提高了5.94%;在考虑外部废热能量输入时,ORC-VCR-CAES系统(火用)效率为51.90%,比常规D-CAES系统提高了4.81%。通过压缩热的回收有效减少了冷却器的(火用)损失,但压缩机组的(火用)损失仍然较大,是系统进一步优化的关键部件;经济性分析表明,当峰谷电价为1.26元和0.30元时,ORC-VCR-CAES系统的项目净现值相比于常规D-CAES系统可增加12.48%,且峰谷电价差越小,ORC-VCRCAES相比于常规D-CAES系统的项目净现值增加百分比越高。

基于压缩式热泵的CO_(2)-MDEA/PZ碳捕集工艺优化

当前化学法CO_(2)捕集系统的高投资、高吸收液再生能耗和高运行费用成为限制其大规模应用的主要障碍。为了回收解吸塔塔顶蒸汽中的潜热与显热,促进解吸反应的进行,利用Aspen plus软件建立基于压缩式热泵技术的有机胺法捕集CO_(2)流程模拟模型,主要探究了解吸塔塔底压力、进解吸塔富液温度、有机工质气化率以及工艺流程对CO_(2)再生过程的影响。结果表明:有机工质R123制热系数较R141b和R245fa高,其性能系数(COP)高达2.35,而排气温度较R141b和R245fa更低。压缩式热泵采用R123为循环工艺介质,热泵回收的热量用于加热贫富液换热器后的热富液以降低吸收液再生能耗。综合考虑解吸系统的再生能耗、工质循环量和解吸效果,通过12级位置注入15%的富液比合适。热泵回收余热工艺的投资回收期为0.82 a,具有较高的经济价值。

铅锌冶炼渣基胶凝材料固化电镀污泥研究

电镀污泥是含有各类重金属的危险废物。本文利用铅锌冶炼渣制备胶凝材料,评估该胶凝材料对固化电镀污泥效果,并阐明了有机聚合物对固化过程的影响机制。结果表明,在碱含量为3.5%(质量分数)、水玻璃模数1.4、液固比0.22条件下,铅锌冶炼渣基胶凝材料可安全固化2.5%(质量分数)的电镀污泥;与未加有机聚合物相比,加入有机聚合物后复合胶凝材料对电镀污泥的固化量提高一倍,同时抗压强度提高27.45%,此时总Cr浸出浓度从20.05 mg/L降低至13.65 mg/L,低于《危险废物鉴别标准浸出毒性鉴别》(GB 5085.3—2007)规定的限值。固化体的矿物组成、微观形貌、化学键和原子价态分析表明,在铅锌冶炼渣中Fe(II)和有机聚合物共同作用下,能有效降低Cr毒性,提高重金属离子固定率。本研究为安全处置电镀污泥及综合利用铅锌冶炼渣提供了新思路。

铜尾矿浆絮凝沉降及对固化影响研究

为研究不同絮凝剂单掺及复配对铜尾矿浆的絮凝沉降效果,选用传统无机絮凝剂硫酸铝、无机高分子絮凝剂聚合氯化铝(PAC)及有机絮凝剂阴离子聚丙烯酰胺(APAM)进行单掺及2种无机絮凝剂分别与APAM复配絮凝沉降试验,并将絮凝后的铜尾矿浆进行水泥固化试验。结果表明:在最佳投加量时,3种絮凝剂絮凝效果为APAM>PAC>硫酸铝。在复配试验中,复配组合的沉降效果均优于单独使用。絮凝前后的铜尾矿固化体抗压强度各龄期最低提高了2.4倍,其中,单独使用絮凝剂硫酸铝后的铜尾矿固化体各龄期抗压强度最高,APAM最低;而在复配絮凝剂中,硫酸铝与APAM絮凝后的铜尾矿固化体抗压强度较PAC与APAM絮凝后的高。

海相淤泥质固化土强度劣化规律试验研究

针对海相淤泥质软土中水泥搅拌桩成桩效果不佳的问题,选取天津地区某地铁工程施工现场海相淤泥质黏土,通过室内水泥土无侧限抗压强度试验,研究了可溶性盐和有机质含量对海相淤泥固化的无侧限抗压强度(UCS)的影响,并通过扫描电镜(SEM)和X射线衍射(XRD)对其微观结构和物相特征进行分析。结果表明:土壤水泥的强度随可溶性盐和有机质含量的增加而降低,其主要通过破坏和抑制水泥水化产物的形成,进而降低水化产物的胶凝性能,破坏了水泥土结构,导致强度降低。该研究结果对解释海相淤泥质软土固化效果不佳的现象具有重要的意义。

有机质含量对水泥土强度影响的室内定量研究

采用对盐城泻湖相软土掺入不同含量的有机质作为试料土,进行了大量的水泥加固室内试验。对试验结果进行了分析,提出了不同有机质含量软土水泥加固后的室内无侧限抗压强度的预测公式,同时建立了不同有机质含量的试料土经水泥加固后的室内强度比与有机质含量之间的定量关系,该定量关系式可以有效地对有机质含量在5.5%～17.5%的水泥加固后的无侧限抗压强度进行定量的预测。

植被混凝土有机质类型与配比的合理选取

为同时保证植被根系生长需求和坡面稳定，需通过试验确定植被混凝土有机质合理类型与配比。选取4种常见富含有机质材料（稻壳、锯末、玉米酒糟、稻谷酒糟），以有机质类型和掺入量为变量，分别试验研究了其对植被混凝土孔隙率和无侧限抗压强度的影响。试验结果表明：植被混凝土孔隙率增幅随有机质配比增加而逐渐减小，无侧限抗压强度降幅则随有机质配比增加而增大；有机质的合理类型为小粒径粉末状有机质，合理配比范围为7％～9％。

改性有机粘结剂对球团性能的影响分析

选择了不同改性剂对有机粘结剂进行改性研究,对有机粘结剂和改性有机粘结剂进行了球团性能对比试验。结果表明:相比于有机粘结剂,选用0.1%硼砂作为改性剂更好,改性有机粘结剂制备的生球团各项性能都有提高,可降低粘结剂用量,节约成本。在改性有机粘结剂添加量大于0.25%时,满足球团生产、运输和冶炼要求。