2021 Moratuwa Engineering Research Conference (MERCon)最新文献_第10页

Comparison of Experimental Results with Empirical Relationships for Energy Losses in Pipe Flow 管道流动能量损失的实验结果与经验关系的比较

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525661

Logeepan Yogaraja, Narmada Liyanagamage, K. De Silva

{"title":"Comparison of Experimental Results with Empirical Relationships for Energy Losses in Pipe Flow","authors":"Logeepan Yogaraja, Narmada Liyanagamage, K. De Silva","doi":"10.1109/MERCon52712.2021.9525661","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525661","url":null,"abstract":"Estimation of energy losses in pipe flow is a prerequisite in designing pipe networks to verify the energy requirement in transferring fluid between two locations. There are two types of such energy losses namely: major losses which is caused by friction at the interface of pipe and the flow and minor losses which is caused due to local conditions such as sudden contractions, sudden expansions, and bends of the pipeline. In this paper, major and minor losses in pipe flow, calculated from empirical equations are compared with the experimental results using PVC pipes which is a popular commercial pipe category. For comparison on minor losses; Bend, Gradual contraction, Elbow bend, Gradual expansion, and 45 degrees bend which are widely used in distribution networks were used and coefficient of minor losses was used as a comparative factor. For comparison on major losses; PVC pipes with five different diameters were used and head loss vs Reynolds number variation was considered in the comparison. According to the results, the Blasius (1913) equation was found to be more accurate for actual flow, while using the Darcy-Weisbach equation found to be more predictive of the major head losses of water flow in PVC pipes.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"13 1","pages":"522-527"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87815510","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: 0

Effective Stress Coefficient through MFEM and Confining Pressure Dependency of Bibai Sandstone Bibai砂岩MFEM有效应力系数及围压相关性研究

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525737

A. Dassanayake, Y. Fujii, A. Thirukumaran

{"title":"Effective Stress Coefficient through MFEM and Confining Pressure Dependency of Bibai Sandstone","authors":"A. Dassanayake, Y. Fujii, A. Thirukumaran","doi":"10.1109/MERCon52712.2021.9525737","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525737","url":null,"abstract":"Fluid in porous rocks affect the performance of rock structures and thus it is important to determine the effective stress in wide range of rock engineering applications. In this study, Bibai Sandstone, a hard-clastic rock, was subjected to multistage and single stage triaxial tests to determine the coefficients of effective stress corresponding to peak and residual strength states ($alpha_{-text{Peak}}$ and $alpha_{-text{Residual}}$) through, Modified Failure Envelope Method (MFEM). The coefficients of effective stress of intact and fractured Bibai Sandstone specimens ($alpha_{-text{Biot}^{prime}mathrm{s}}$ and $alpha_{-text{Fractured}}$) were determined using hydrostatic compression test and compared with the values obtained for $alpha_{-text{Peak}}$ and $alpha_{-text{Residual}}$ by MFEM. Microstructure analysis was carried out on the images of blue resin impregnated thin sections using Imagej software and a post-compression macrostructure analysis was performed using micro-focus xray computed tomography (CT). $alpha_{-text{Biot}^{prime}mathrm{s}}$ and $alpha_{-text{Peak}}$ decreased with increasing confining pressure which was related to the microstructure of the rocks. Further, the applicability of MFEM were discussed.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"143 1","pages":"409-414"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86581195","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: 0

A Reflection on Assessing Learning Outcomes 关于评估学习成果的思考

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525791

M. Hettiarachchi

引用次数: 0

Evaluation of RANS Turbulence Models for Prediction of Lateral Film Cooling Effectiveness at Low Blowing Ratios 低吹风比下RANS湍流模型对侧气膜冷却效果预测的评价

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525723

Pasan Sanjeeva, E.G.D.R. Thilakarathna, Chanaka Mallikarachchi, Chathura Ranasinghe

{"title":"Evaluation of RANS Turbulence Models for Prediction of Lateral Film Cooling Effectiveness at Low Blowing Ratios","authors":"Pasan Sanjeeva, E.G.D.R. Thilakarathna, Chanaka Mallikarachchi, Chathura Ranasinghe","doi":"10.1109/MERCon52712.2021.9525723","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525723","url":null,"abstract":"Accuracy of numerical predictions of film cooling performance is vital to investigate for designing and analyzing film cooling technology. Three RANS turbulence models of Standard k-$varepsilon$ (SKE), Standard k-$omega$ (SKW) and Shear Stress Transport methods (SST k-$omega$) were selected and used to simulate low blowing ratio cases ($mathrm{M} < 1$). The three blowing ratio of 0.2, 0.5 and 0.7 were produced using an inclined cylindrical hole of 30 degree made on a flat plate. ANSYS CFX solver was used to simulate the selected experimental cases with density ratio (DR) of 1.8. The numerical results of the three turbulence models under the blowing rate of 0.2 have not captured the lateral distribution of coolant correctly. SKW under the blowing rate of 0.5 have accurately predicted the effectiveness in mixing region. Centerline adiabatic effectiveness generated by SKW model was in a good agreement with experimental results for the blowing rate of 0.5. For the blowing rate of 0.2, the centerline effectiveness were best predicted by the SST model while SKW and SKE models can be used to predict the adiabatic effectiveness with considerable accuracy in lateral direction in the region of $mathrm{X}/mathrm{D} < 10$.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"68 1","pages":"339-344"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76528097","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: 0

Enhancing the Capabilities of Approaching to Service Scenarios and Settling for Intelligent Wheelchair Robots 提高智能轮椅机器人的服务场景逼近与解决能力

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525668

Hiroshaan Vadivel, K. S. Priyanayana, A. Jayasekara

引用次数: 0

Fine-Tuning Self-Supervised Multilingual Sequence-To-Sequence Models for Extremely Low-Resource NMT 极低资源NMT的微调自监督多语言序列到序列模型

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525720

Sarubi Thillainathan, Surangika Ranathunga, Sanath Jayasena

{"title":"Fine-Tuning Self-Supervised Multilingual Sequence-To-Sequence Models for Extremely Low-Resource NMT","authors":"Sarubi Thillainathan, Surangika Ranathunga, Sanath Jayasena","doi":"10.1109/MERCon52712.2021.9525720","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525720","url":null,"abstract":"Neural Machine Translation (NMT) tends to perform poorly in low-resource language settings due to the scarcity of parallel data. Instead of relying on inadequate parallel corpora, we can take advantage of monolingual data available in abundance. Training a denoising self-supervised multilingual sequence-to-sequence model by noising the available large scale monolingual corpora is one way to utilize monolingual data. For a pair of languages for which monolingual data is available in such a pre-trained multilingual denoising model, the model can be fine-tuned with a smaller amount of parallel data from this language pair. This paper presents fine-tuning self-supervised multilingual sequence-to-sequence pre-trained models for extremely low-resource domain-specific NMT settings. We choose one such pre-trained model: mBART. We are the first to implement and demonstrate the viability of non-English centric complete fine-tuning on multilingual sequence-to-sequence pre-trained models. We select Sinhala, Tamil and English languages to demonstrate fine-tuning on extremely low-resource settings in the domain of official government documents. Experiments show that our fine-tuned mBART model significantly outperforms state-of-the-art Transformer based NMT models in all pairs in all six bilingual directions, where we report a 4.41 BLEU score increase on Tamil→Sinhala and a 2.85 BLUE increase on Sinhala→ Tamil translation.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"32 1","pages":"432-437"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90082783","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: 9

Effects of Current Density on the Solder Wettability of Nickel Electrodeposited Ni20Cr Alloy 电流密度对镍电沉积Ni20Cr合金钎料润湿性的影响

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525762

A. Kumarasiri, H.S. Herath, D. Amarasinghe, D. Attygalle

{"title":"Effects of Current Density on the Solder Wettability of Nickel Electrodeposited Ni20Cr Alloy","authors":"A. Kumarasiri, H.S. Herath, D. Amarasinghe, D. Attygalle","doi":"10.1109/MERCon52712.2021.9525762","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525762","url":null,"abstract":"Nickel-chromium alloys are in high demand in the electrical industry, as they have some favorable electrical properties. The formation of a thin chromium oxide layer on the alloy surface protects the alloy from further oxidation. The passivation layer formation is almost instantaneous when exposed to the ambient atmosphere. It prevents the strong bonding between the solder and the substrate due to the alteration of the substrate's surface energy by the passivation layer. Poor solderability could cause short-circuiting and resistance variations in electrical devices. This paper reviews the effect on solderability due to the passive layer formation and proposes solutions to overcome the problems caused by this layer. The introduction of solder-compatible metal layers such as Ni onto the substrate surface is a way to overcome this. However, solder-compatible metals such as Ni cannot be introduced with conventional electroplating baths due to the alloy's passive behavior. Therefore, a breakdown of the passivity is required before the nickel coating. A three-bath electrodeposition strategy comprising; pre-cleaning, activation, and electroplating, were used to achieve the task. The study examines the dependency of solder wettability on the current density, using an in-house fabricated contact-angle measuring device and analytical software.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"7 1","pages":"649-653"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90084002","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: 0

Quadcopter Disturbance Estimation using Different Learning Methods 基于不同学习方法的四轴飞行器干扰估计

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525652

Sachithra Atapattu, O. de Silva, G. Mann, R. Gosine

引用次数: 0

Multi-Step Bidirectional LSTM for Low Frequent Bus Travel Time Prediction 基于多步双向LSTM的低频公交行程时间预测

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525709

Sudeepa Nadeeshan, A. Perera

引用次数: 0

Characterising the Self-opening Behaviour of Single Creased Kapton Polyimide Films 单折痕卡普顿聚酰亚胺薄膜自开特性的表征

2021 Moratuwa Engineering Research Conference (MERCon) Pub Date : 2021-07-27 DOI: 10.1109/MERCon52712.2021.9525790

Sutharsanan Navaratnarajah, Chermila Piyumi, Chinthaka Mallikarachchi

{"title":"Characterising the Self-opening Behaviour of Single Creased Kapton Polyimide Films","authors":"Sutharsanan Navaratnarajah, Chermila Piyumi, Chinthaka Mallikarachchi","doi":"10.1109/MERCon52712.2021.9525790","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525790","url":null,"abstract":"Use of thin folded membranes for deployable structures are becoming increasingly popular especially in aerospace applications such as a deployable solar array, sun shields, and solar sails. The folding and compaction process of thin membranes, which introduces permanent, nonrecoverable, localized plastic deformation, changes the geometric shape and material properties. The underlying mechanics in the deployment of creased membrane structures are self-opening and then forced-opening beyond a stable stress-free state. The focus of the previous studies was limited to the characterisation of crease behaviour during force opening. This paper presents an experimental study to characterise the crease mechanics of a single creased membrane during self-opening behaviour which is crucial in the design of gossamer structures. A simple analytical study was performed to predict the moment-rotation response of the crease and hence shows a good qualitative agreement with physical experiment results. It is shown that the moment-rotation response of a single crease can be idealized to a linear rotational spring in virtual simulation and the spring stiffness depends on the thickness of the membrane.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"19 1","pages":"130-135"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84224467","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: 0