Challenges and opportunities of distance learning and teaching

A.A.Y.Hansini

Undergraduate

University of Jaffna

Challenges and opportunities of distance learning and teaching

        Distance learning is not a strange phenomenon hence it is been started a several centuries ago. An English educator, Sir Isaac Pitman used shorthand by mail to teach in 1840.The university of London is the first university who becomes offer distance learning degrees. In late 1900, distance learning transformed as e-Learning as a result of technological revolution. Now, the distance learning is a complex system that include Government policies, loans, databases, working methods etc. Due to the COVID-19 pandemic situation, all colleges, institutes and universities paid their attention to distance learning.

 What is the most important factor in distance learning and teaching?

It is the network. The world wide web is used to e-learning. Nowadays, the online learning has been transformed from the kindergarten to higher education systems. This results a rapid increasing demand to internet.

 What is the biggest challenge Sri Lanka facing in distance learning and teaching?

The biggest challenge Sri Lanka faces in this evolution, having a poor network bandwidth. As per Surf shark digital quality of life index, Sri Lanka’s index value is 0.457. Further, in rural areas of Sri Lanka, the signal strength is very low. Students who live in these places have to climb up mountains, trees or whatever higher place that indicate strong mobile signals. Also, adapting to unfamiliar methods and technology is another challenge.

In addition, E-learning platforms such as zoom, Microsoft Teams, Google Meet occur unknown errors. Unstable power & energy breakups might be occurred. Also, all typical routers do not have a charging method as mobile phones which can charge using power banks. Also, laptops do not have methods to charge if a power failure occurs.

Further, poverty is another obstacle Sri Lanka faces. Due to this reason, most of the students do not laptops which can the students learn in more comfortable manner.

 Have you ever slept while in a zoom call?

This is another challenge in distance learning. All the participants are connected through the internet. Students’ microphones and cameras are off. Teacher or lecturer delivers their content. Hence, we do not have any live sense. Thus, participants get distracted easily. Some of them are asleep, some of them do another irrelevant work during the lecture. Also, when downloading or uploading course materials errors might be occurred. When learning or teaching in institutional place, the students can gather and have informal and formal communications with colleagues. This results to stay motivated and energetic in learning or teaching.

 

Completing Intended Learning Outcomes (ILO) is the important achievement to the students. When Distance learning occurs, it saves time with easily delivering quizzes, viva and assessment submissions. These are the Opportunities in Distance learning. On the other hand, institutes don't want to print lot of notes or whatever learning materials. This cause to reduce the papers and it saves trees in the world. Green world is a sustainable development goal. Start from a little thing that we need today. These are the opportunities of distance learning and teaching .

T.D. Athapaththu
Undergraduate
University of peradeniya

Organic Farming, Its Relevance in the Sri Lankan Context, and the Engineer's Role

    Amila Premakumara

    Undergraduate

    University of Moratuwa

 

Challenges and opportunities of distance learning and teaching

 

M.J.F. Aasifa

Undergraduate

University of Jaffna

AURA VIA GADGETS

View EPISODE- 04

EPISODE 5

The plane landed at 2.50 am at the Vizag international airport. They took a taxi from the airport for the next part of the journey. It drove them into a countryside village through a narrow road with huge palm trees alongside.

The soulful singing of ‘bajans’ they heard on the way was such a wonderful blessing in the early morning. They were so amazed and overwhelmed by these new experiences. It was a bit hard to clear out their doubts as the driver was a native speaker and communicated with them in poor English. The taxi reached a small hotel which was the highest recommended luxurious hotel in the entire village. The accommodating arrangements were done perfectly by his friend Nair. Sethu and Neena fell fast asleep among the bajans as they calmed down both their bodies and souls.

Neena got up early and freshened up to go outside as she knew the place well, but now it has changed a bit. Pure air carries chemical mixed smokes too now. The huts have also turned into buildings with many pillars. Human settlements conquered the area around the ‘Ashram’ for business after the arrival of thousands of soul seekers to the ‘Ashram’

Neena sighed at the sight of the environment now. She remembered the calm and beautiful village, she saw six years back. ‘Demand increase when the needs of population increase with the time’ she thought. Her bare feet kissed the earth. She stretched her hands in the air, closed her eyes, and moved her face upwards to feel the refreshing breeze. Neena felt the peace inside her and listened to her heartbeat only. This took her to the limitless and eternal inner world. She couldn’t escape from the magnanimous happiness. However, she returned to the worldly callings within a few minutes. Neena walked towards the ‘Ashram’ eagerly to meet the ‘Head’ of it whom they called the ‘Guruji’. Back then, she learned to count her breaths to gain control over her mind. Her soul started to feel eternal happiness when she stepped into the compound of the ‘Ashram’. Guruji welcomed Neena with a cheerful hug and introduced her to the new practitioners of the ‘Ashram’. Guruji and Neena had a long conversation about the changes that happened in the lives while walking in the green meadow. Neena requested Guruji to guide Sethu. Guruji humbly replied, “Neena, you know that if someone knows himself fully then he knows everything”. Neena smiled and agreed with a nod. At that time Sethu appeared there with a little girl who took him to the ‘Ashram’ along. Guruji stopped Sethu before he was going to open up about him, and he asked him to count his breathing without any other thoughts. Sethu dropped a weird blink on Neena and he couldn’t catch up. Guruji left the place slowly and calmly. There was a dreadful silence between them and Neena broke it up by calling him for breakfast. A fine morning went up with leafy porridge for the first time in the life of Sethu. Everything around him seemed very new to him. Day by day this practice of soul’s peacemaking improved and Sethu was trained well to distinguish the inner voice and their impacts. Sethu transformed himself into a new spiritual person without any tools or machines in his hands. He found himself for the first time in his meditations, and later he got more ideas to carry his experiments with the help of his inner voice.

 

After 10 months, Sethu realized the purpose of his birth and started to work on identifying the inner voices related to metaphysics. Thousands of ideas failed along with hundreds of experiments. Sethu found that he is in a particular range of frequency levels while he was meditating or when he shut all his sensory organs. All of his energy is invested at a time when he was in the position shut mode. He made hundreds of ENGs (Electro Neuro Graphs) of himself to identify the frequency range when his inner voice talked to him and succeeded. Normally ENGs record the vibration of the neurons while functioning. Sethu’s ENGs showed a similarity with Neena’s ENGs when they both were meditating. A few months later, finally, Sethu invented Electro Inner Voice Reader (EIVR) in India. He knelt and thanked God for his amazing gift. For the first time, he read the thoughts of Neena via his EIVR and felt warm inside him. Sethu held her hand firmly and murmured to her left ear about his heartiest wish. Neena’s eyes dropped a tear for the first time….

The End...

Story by:

L.Pirashanthiyah

Department of Electrical Engineering

Faculty of Engineering, University of Moratuwa

Artist:

Achini Fonseka

Department of Textile and clothing technology,
Faculty of Engineering, University of Moratuwa

Role of Self-Compacting Concrete (SCC) in sustainable development

Concrete is the premier material that performs the major integral role in shaping the environment, providing the essential infrastructure for industries, transportation, accommodations, and energy production. The concrete industry tries to minimize the adverse impacts on the environment by reconciling the advantages and disadvantages of sustainable concepts during production, mixing, casting, and curing by facing challenges with innovative measures. It contributes to the current climate changes and concerns about the consumption of energy efficiently. According to the Energy Performance of Building Directive (JI, T., 2006), “the residential and tertiary sector, the major part of which is buildings, accounts for more than 40% of final energy consumption in the community and is expanding, a trend which is bounded to increase its energy consumption and hence also its carbon dioxide emissions”. Now the concern for the selection of construction material is dominated by ecological considerations and the growing sustainability ethics along with efficient use of the resource, health and safety, and improved productivity with fewer wastages. 

Sustainability in SCC production

SCC was proposed and developed by Prof.H.Okamura of University of Tokyo, Japan around 1988 as a solution for the problem of the low quality of structures resulting due to the lack of proper compaction of concrete. The SCC is a material that flows and gets compacted under the influence of self-weight only, without vibration and additional process emerged. Due to specific composition, a high fluidity of SCC allows for complete filling formwork and achieving full compaction, even in the presence of congested reinforcement. The density and homogeneity of hardened concrete are high and it gives the same engineering properties and durability as traditionally vibrated concrete (TVC) [1]. According to the high demand associated with sustainable development, a new type of SCC was developed with reduced cement content and diminished carbon footprint value since earlier SCC was not attractive with its high content of cement. As per Wallevik, this aspect of SCC is classified in Table 1 [2].

Self-compaction is defined by deformability, followability, and cohesiveness. SCC needs high viscosity and high deformability and these aspects are directly connected with the fluidity. When fluidity is increased by the high-range water reducer, it affects the stability which can be solved by providing constant water/cement ratio and sand content. However, the cohesiveness of SCC is reduced by the excessive dosage of high-range water reducer [3]. This can result in a higher degree of segregation and heterogeneity than normal concrete of similar water/cement ratio and lower fluidity. As a solution, a viscosity agent can be added to increase the water phase viscosity. On the other hand, the viscosity of fresh SCC can be increased by accumulating the solid fraction of the paste phase of concrete. Cement content can be increased to roll up the number of fines [4]. But, the excess amount of cement will greatly increase the cost of materials and the evolution of heat which can result in higher shrinkage. Thereupon, the use of materials of low reactivity finely ground materials will be the preferable method to provide necessary workability.  Hence, the main factor in the mix design of SCC is the increase in the power content to improve the separation of aggregate particles. Using cement as entire powder content is not sustainable in an economic and environmental manner. Recycled urban and industrial wastes such as fly ash are used as a replacement for cement. These replacements assure the production of sustainable SCC into the range of normal and high compressive strength class of SCC. When a substantial amount of cement is replaced with supplementary cementitious materials in concrete mixes, the environmental impact of concrete can be significantly reduced [5].

zAccording to Jacob and Hunkeler (2001), as the difference between standard concrete and SCC can be clearly stated that SCC requires higher binder and admixture content. The properties of different compositions of concretes were studied at the age of 28 days as presented in Table 2 [6].

The values shown in table 2, explain the difference in durability. The enhancement of the durability of concrete is the premier advantage achieved from the invention of SCC. The variation in water/powder ratio gives an idea regarding the mechanical resistance. The chloride diffusion coefficients deal with the use of ultra-fine material (the addition of minerals) which can cause environmental impacts as presented in table 3 [6].

Collectively both table 2 and table 3 shows the improvement in compressive strength. In terms of environmental impacts, it can be mitigated with the addition of industrial wastes such as fly ash, blast furnace slag, and silica dust as cement replacement and that can be classified according to the fine content as shown in the table 1. When cement is reduced, the fresh concrete will segregate. This can be solved with the introduction of special aggregate grading characterized by high fine content without colloidal particles. The low cement SCC leads to low consumption of material cost, less shrinkage, and reduced risk for crack formation due to the reduced paste volume in concrete.

Sustainability in Construction

The production of SCC is an energy conservation process, as the electricity consumption for vibration is eliminated. The SCC mixture incorporates industrial wastes such as fly ash, silica fume, and quarry dust and ensures sustainable production. It increases the lifespan of construction molds and reduces the necessity of skilled workers. SCC can be used for all types of structures due to the fact that it can be pumped at long distances without its segregation (Atkins, H.N., 2003). When vibration is omitted from casting operations the workers experience less strenuous work with significantly less noise and vibration exposure (Okamura, H., 2003). Nearly 0.11 kg of CO₂/m³ emits while using a flexible stick – type vibrator [7]. Similarly, the vibrator creates a 75-80 dB noise level [8]. These vibration and noise eliminations from construction ensure following the sustainability concept and occupational health and safety practices.  The environment gets rid of harmful continuous high-frequency noises and mechanical vibrations. Due to the elimination of external vibration, the probability of damages is abated with the increase of durability comparing to normal vibrated concrete. SCC is placed without the need for compaction using vibrating pokers and it provides solutions for the health-related issues-particularly “white finger” caused by mechanized vibration methods. From the contractor’s point of view, concrete placement is much faster with fewer laborers leads to cost reduction. The remedial cost is mitigated hence the structures are finalized with good finishing surfaces. It means, no plaster or other external layers are needed especially in architectural concrete elements: In these elements, concrete is permanently exposed to view. According to the BEES program developed by NIST, during the production and application of a 1 m² of cement plasterwork, approximately 0.57 kg of CO₂ emission is taken place [8]. As an architectural concrete element, the larger surface exposure increases the carbonation process. Thus, CO₂ uptake will be faster and in a wide range.

Conclusion

Regardless of chemical additives, SCC shows better mechanical properties and durability than TVC. The introduction of industrial waste cementitious materials leads the concrete industry towards sustainable development. Moreover, the use of SCC for infrastructure construction, through its contribution to reducing the manpower and energy requirements, bestows the achievement of the economic sustainability of concrete construction by overcoming the most expensive constituents.

Kavinthan Jeyasingam

Department of Civil Engineering

University of Sri Jayewardenepura

References

[1]   Ali Papzan, Taksiah.A.Majid, M.A.M.Johari, "A Review of Self-Compacting Concrete on Sustainable Development," Australian Journal of Basic and Applied Sciences.

[2]   Wallevik O., Mueller F., Hjartarson B., Kubens S., "The green alternative of Self Compacting Concrete, ECO-SCC," in 35th Conference on OUR WORLD IN CONCRETE & STRUCTURES, Singapore, 2010.

[3]   Oliveira, Luiz Antonio Pereira de, "The sustainable self-compacting concrete technology," Coimbra, 2009.

[4]   P, Billberg, "Fine Mortar Rhelogy in Mix Design of SCC," Proc fitst int Rilem symp on self compacting concrete, pp. 47 - 58, 1999.

[5]   R. S. Ravindrarajah, "High-strength self-compacting concrete for sustainable construction," 2010.

[6]   Jacobs F, Hunkeler F, "Ecological Performance of Self Compacting Concrete," in 2nd International Symposium on Self Compacting Concrete, Tokyo, 2011.

[7]   R. o. M. o. t. environment, Environment and health performance review, Poland: PUBLIC HEALTH ADMINISTRATION, 2009.

[8]   WITKOWSKI, Hubert, "Sustainability of Self-Compacting Concrete," p. 6, 2014.

[9]   Adnan Mujkanović, Marina Jovanović, Dženana Bečirhodžić, Amna Karić, "Self-Compacting Concrete - A sustainable Construction Material," in The 5th International Conference on Environmental and Material Flow Management, 2015.

[10] Heirman G, Vandewalle L, "The influence of fillers on the properties of self-compacting concrete in fresh and hardened state," Proc third int Rilem symp on self compacting concrete, 2003.

[11] B. P, "Fine Mortar Rheology in Mix Design of SCC," Proc first int Rilem symp on Self Compacting Concrete, pp. 47-58, 1999.

AURA VIA GADGETS

EPISODE -03 click here

EPISODE 4

At that moment, the lights went off, a breeze passed slowly and the darkness covered him totally with that tap. Now the heartbeat rate increased to the peak level. Somehow, he managed himself and turned his head back slowly. He wouldn't believe his own eyes. Few drops of sweat have fallen from his head and his eyes also shed two drops. A light body is standing behind him in the air. The next moment, nothing was there and nothing happened neither good nor bad. Millions of thoughts were appearing in his mind and disappearing at the same moment. He couldn't understand anything that was going around him. However, he rushed into the ward to get help and he found no one was awake, but a therapist came from the counselor’s room as of Sethu's screaming. Sethu tried to explain everything to the therapist, so he could analyze the words and reasons for the screaming that night. Then both rushed into the same room where Sethu saw the light body. They searched the room for a long time period but there was nothing new. The therapist made Sethu calm and let him rest for a few minutes and then he described the nature of human-Aura and its form like light body which sparkles for a few moments only. Sethu understood that the light body that disturbed him was an Aura of a person who died at that very moment or before.

Now, both rushed into each ward to check whether somebody died at the moment. It was such a wonder when he found out that one of the patients suffering from a long term disease in the 8^th ward has expired and the doctor-in-charge for that ward verified the death occurred 20 minutes ago. Now Sethu was clear that the light body which patted him was the patient whom he made friends with Sethu while he was studying there. Suddenly he ran to see the camera in the ward to check whether it has recorded the soul-leaving of body. His eyes watered while observing that soul-leaving from the physical body in the form of a white-light layer. He was frozen at that moment and realized that soul worth’s, no matter how the physical body is. He got cleared the worthy connections of the physical body and the soul which lives inside it. It was amazing to listen to the therapist talking about how the soul is lying inside us. Also, she told more weird and unbelievable things about it that Sethu was never aware of. The therapist shared her experiences in this counseling part apart from her spiritual life which she learned and practiced with a monk in India. Little by little, both got closed beyond their search and science. They would fall in love with each other, but Sethu hesitated to express it to the therapist who became half of his heart now. Sooner they became closer by their heart and souls. Neena, the therapist watered the research plant of Sethu and did all he wanted to continue with his studies.

Sethu seemed happy with this new life. He often visited his girlfriend in the evenings. Most of their time was not only romantic but also meaningful working on their research too. Neena showed her spiritual life and helped him to enter the spiritual life entirely by telling her earlier studies from an "Ashram" in India. She insisted a thought to him that science is not the basement for all types of inventions or discoveries. Apart from them all, there is a spiritual world which is the originating point of each and everything including science too. Sethu was inspired by the talks of Neena and praised her for the guidance and support which she gave. It would be better if he married her earlier for his thirst for unknowing things. He understood that if he gets more and more details about the soul-body connection, it will be easier for the next movements. They discussed and decided to first proceed with their studies together. A few days later, both flew to India. Their thoughts flew faster than the flight.....

To be continued...

Story by:

L.Pirashanthiyah

Department of Electrical Engineering

Faculty of Engineering, University of Moratuwa

Artist:

Achini Fonseka

Department of Textile and clothing technology,
Faculty of Engineering, University of Moratuwa