Machine based algorithm for characterizing and precursory monitoring of landslides

Landslides routinely cause significant damage to life and property. Various studies have evaluated mechanisms that trigger landslides. It is now established that a large proportion landslides are caused by a combination of anthropogenic activities and environmental factors such as rain and earthquakes. Das and Tordesillas (2019) proposed a machine based algorithm to characterize and provide precursory warnings for a rockfall type of landslide. In this work we extend this algorithm (Section 3.4) to include relatively short but serially correlated displacement signals sampled with using the interferometric synthetic aperture radars (InSAR) embeded within the sentinel group of satellites. The generalized version of the algorithm is based on spectral analysis of time series. The resulting algorithm is applied to 2019 Brumadinho Tailing Dam collapse. The algorithm identities several potential risk milestones going back to about July, 2018, eventually concluding with two retrospective estimates of risk, tR (27 Feb 2018 - 26 Aug 2018) for definitive but emergent risk and tI (27 Jun 2018 - 24 Dec 2018) for imminent risk of collapse of the system. We posit that the combination of spectral methods and second order statistical properties of displacement signals can reveal tantalizing signs of transition into an unstable regime and argue that this algorithm can also be used for intervention with a view to mitigate the chances of a potential disaster

Effect of resistance band and weight training on throwing velocity of club level baseball players in Sri Lanka

Throwing velocity is undoubtedly considered as one of the crucial factors that affects output of a baseball game. To improve throwing velocity, numerous training methods and approaches are being used. Therefore, the purpose of this study was to find the effect of the resistance band and weight training on throwing velocity of age (27±3), (mean ± SD) club level baseball players in Sri Lanka. Forty baseball players were recruited for the 8-week training program based on the inclusion criteria and availability of players. Initially, athletes were assigned into 3 groups: a control group (n=10), a weight training group (n=15), and a resistance band training group (n=15). The weight training group performed 6 upper body exercises by using barbells and dumbbells while the resistance band training group engaged in 6 upper body exercises with blue and red coloured bands. Moreover, the control group was only allowed to perform their daily routine baseball practices which were 3 days per week and 3 hours per day. Throwing velocity was measured by using a radar gun, and upper body strength was measured using the one-repetition maximum (1RM) bench press test to determine the relationship between strength and throwing velocity. Both test results were evaluated by using pre-test and post-tests’ descriptive and inferential statistics. The weight training group and the resistance band group showed significant differences in 1RM bench press and the radar gun tests while the control group showed only a significant difference in the strength test. In addition, the control group revealed no significant difference in throwing velocity. Furthermore, the weight training group showed the greatest improvement in throwing velocity and 1RM bench press tests, and then the resistance band group followed the same. In conclusion, Strength training and resistance band training can be utilized to develop strength in the upper body and it may help to develop throwing velocity in other throwing sports, such as cricket, throw ball and so on. KEYWORDS: Throwing Velocity, Weight Training, Resistance-Band Training, Radar Gun Test, 1RM Bench Press Tes

Importance of consistent cement quality for a sustainable construction

The EN and SLS specifications for Portland cement have largely similar provisions on physical and chemical parameters of cement. However, consistency of cement within standards specifications is significantly high and it affect to standard deviation of concrete. In order to obtain good concrete quality, concrete users need to target a low standard deviation of concrete strength. In order to reduce the strength standard deviation of concrete strength, the material properties variations need to be lowered. This paper discusses variation in cement properties from 5 different cement suppliers. Cement from given suppliers varies between batches/ shipments. It is well understood that there are significant differences in mortar strength, chemical composition, fineness, setting times of same cement type (Type 1) from different suppliers. Experiments were conducted with 48 cement samples of 5 different cement suppliers collected over 10 months time from January 2011 to October 2011. It was found that as all cement brands comply with EN and SLS standards. However, coefficients of variation (COVs) of most parameters, especially strength, are significantly high. This paper answers two key questions; are all nominally similar cements the same? Does cement from same supplier always behave consistently? Finally it recommends cement users and specifies a systematic way to select a consistent cement supplier for an economical and sustainable construction

The Effect of Hydrogen Peroxide based Hand Sanitizing Chemicals on the Physicomechanical Properties of the NBR Gloves

During the Covid-19 pandemic, according to the guidelines given by the World Health Organization (WHO), all industrial and examination gloves are subjected to disinfection globally using hand sanitizers. This may affect the physicomechanical properties of the gloves. However, limited data are available regarding the aforesaid issue. This research is focused on investigating the effect of hydrogen peroxide-based hand sanitizer formulations, recommended by WHO on the chemical and physicomechanical properties of NBR gloves. NBR gloves were exposed to sanitizing chemicals with different application frequencies for eight hours and the properties were evaluated after 48 hours. The results revealed that there is no significant effect of sanitizer formulation on the mechanical properties of NBR gloves such as tensile strength, tear resistance, elongation at break, modulus at 100%, and 300% even at high frequent applications. Physical properties such as discoloration, swelling, and leakages were also not affected by the application of sanitizers. Further, DSC and TGA test results revealed that there is no significant change in crystallinity and thermal properties between control and test samples. However, FT-IR analysis indicated a change in the chemical environment of the surface of the glove specimens. Since FT-IR is a surface analysis technique, it can be identified as the surface of the gloves has been affected by the exposure to sanitizer formulations. Nevertheless, the inadequate time for the hand sanitizing chemicals to be penetrated to the core of the gloves might result in unchanged physicomechanical properties within 48 hours. Knowing the fact that the examination gloves have a very short usage time, it can be concluded that the effect of hydrogen peroxide-based hand sanitizer formulations on NBR examination gloves is negligible. However, we highlight the importance of conducting further research for an extended period to evaluate the effect of the exposure on heavy-duty NBR gloves such as industrial gloves

Urea-Hydroxyapatite-Polymer Nanohybrids as Seed Coatings for Enhanced Germination

Modern agriculture practices play a vital role in fulfilling the doubling food demands of the increasing population. In particular, several attempts have been made to enhance the nutrient supply and plant uptake process in different growth stages of plants, but little effort has been made to enhance the nutrient status of the seeds at the seedling stage. At this stage of growth, phosphorus is the most essential nutrient, and the requirement is high, while nitrogen requirement is very low. This study focuses on developing a seed coating containing urea-modified hydroxyapatite nanocomposite to supply N and P to the seedlings in a controlled manner throughout the early growth stage. A nanohybrid based on urea-modified hydroxyapatite was synthesized using an in-situ sol-gel method and further combined with an alginate/cellulose polymer to develop the coating. Seed coating was realized using a dip coating method containing calcium chloride as the cross-linking agent. Seed germination experiments were conducted under laboratory conditions according to a randomized complete block design under constant light conditions, controlled humidity, and temperature. The structural features of the nanocomposite were studied using powder X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopic data was used to analyze the morphology. The formation of HA nanoparticles was confirmed by powder x-ray diffraction patterns that revealed the characteristic peaks for (002), (211), (300), and (202) planes of HA. Furthermore, the successful insertion of urea into the HA lattice was corroborated by both the powder X-ray diffraction and Fourier transform infrared spectroscopic techniques. Nanocomposite coatings of 50 -100 μm demonstrated excellent compatibility with the surfaces of the seeds. Seed coating composed of hydroxyapatite-urea (1:0.3) treatment revealed an increase of 124.6%, 147.6%, 100%, and 166.7% in average biomass, root length, number of roots, and maximum plant width, respectively, compared to the control, after 21 days of planting.Keywords: Urea Modified Hydroxyapatite, Nanocomposite, Alginate, Carboxymethyl Cellulose, Seed Coating, Germination

Living Fences, a Widespread Agroforestry Practice in Sri Lanka: Two Cases from Dry and Intermediate Zones

The study was conducted to examine the structure and composition of live fence agroforestry practices in two regions of Sri Lanka and to identify key ecosystem system services provided by them. The studies were conducted in the Katupotha in Kurunegala district and Hingurakgoda in Polonnaruwa district. Species composition including dominance, diversity and sinusial formation were evaluated. Highest average relative importance, relative frequency and dominance values were obtained by Wetahira (Gliricidia sepium), Wetaendaru (Jataropha curcus) and Sudu araliya (Plumeria obtusa) at Katupotha and Teak (Tectona grandis), Wetahira (Gliricidia sepium), Ipil-ipil (Leucaena leucocephala), Neem (Azadiracta indica) and Yakadamaran (Syzygium zeylanicum) at Hingurakgoda. The RIV value shows that live fences of Katupotha was dominated by typical (structural) live fence trees (Over 90% dominance) whereas live fences at Hingurakgoda was dominated by high value timber trees (Over 60% dominance). The results indicate that living fences have high species diversity. A total of 72 species were recorded from the living fences in two sites. Live fences at Hingurakgoda were often more diverse than Katupotha although the total number of species recorded at Katupotha site (68) was more than that of Hingurakgoda (25). 21 out of 25 (84%) species recorded at Hingurakgoda were also recorded from Katupotha. Hence species reported at Hingurakgoda is almost a subset of species identified from living fences at Katupotha. The Index of Similarity for two sites (plant communities) was 0.58 as 21 out of 72 (29%) species were found common to both sites. The study clearly shows that live fences in addition to acting as protective structures against theft of homegarden produce, entry of stray animals and encroachments also could make further contributions to the environment and mankind due to high biodiversity. They include provisioning of timber, food, medicine, fruits, vegetables and fodder for livestock regulatory functions such as shade, windbreak and enrichment of soil fertility and cultural services such as visual amenity due to having ornamental plants. Further this study indicates that there is lot of potential for further enriching these live fences to better perform ecosystem services. Since live fences are a common farming practice spanning all agro-ecological regions of Sri Lanka, they could serve as a place for conservation of species and tool for identification and evaluation of species for different regions and purposes

Nanomaterials for smart energy systems: from led to Supercapacitors and solar cells.

It has been forecast that there will be a severe impact on world economics and ecology in future by energy consumption/production that rely on the combustion of fossil fuels. Therefore more sustainable and more environmentally friendly alternative energy/power generation sources are currently under serious consideration. One such alternative is electrochemical energy production. Systems for electrochemical energy storage and conversion include batteries, fuel cells and electric double layer capacitors (EDLCs). Although the energy storage and the conversion mechanisms are different, there are “electrochemical similarities” of these three systems. Electric double layer capacitors, also known as supercapacitors or ultracapacitors, have tremendous potential as high energy high power sources for use in low weight hybrid systems. Commercial applications for such devices include uninterruptible power applications, telecommunication and transportation. The total energy stored in a conventional capacitor is proportional to both the number of charges stored and the potential between the plates. Essentially the former is a function of the size of the electrode while the later is determined by the breakdown of dielectric between the plates. Different voltages, hence energy stored, can be generated when different dielectric materials are used to separate the plates. Materials can be optimized to produce high energy densities for a given size of a capacitor. In contract to conventional capacitors, supercapacitors do not have a conventional dielectric. Instead, two layers of the same substrate and their electrical properties are used in order to effectively separate the charges despite vanishingly thin (on the order of nanometer) physical separation of the layers. Higher energy storage density can be achieved in supercapacitors when nanomaterials or materials with nanoporous structure are used because such materials offer enormous surface to volume ratio. Activated carbon is a material with unique properties especially in relation to its nanoporosity and can therefore be used in supercapacitors. Sri Lanka is one of the worlds’ best coconut shell based activated carbon producer. Besides, carbon nanotube (CNT, either MWCNT or SWCNT) can also be used in supercapacitors as electrode material where charge storage capacity can be increased to a much higher value. Ceylon vein graphite is a good source for the production of CNT. Further, the use of nano-TiO2 in conjunction with light absorbing material in cost effective solar cells is a well established process. The charge carrier generation process in solar cells mimics natural photosynthesis (green energy). At present such solar cells have efficiency nearly 11 %. Again Sri Lanka inherits a vast naturally occurring TiO2 deposit, the range of benefits of which is yet to be explored and harvested to produce nano-TiO2. Therefore nanomaterials in Sri Lanka has a wide spectrum of application and in this presentation, the opportunities to develop smart energy systems using Sri Lankan nanomaterials will be presented

Preservation of fresh coconut gratings by hurdle technique

Hurdle technology employs the intelligent combination of different preservation factors to achieve mild but reliable preservation effects. Fresh coconut gratings treated with different combinations of hurdles such as acidulants, humectants, preservatives, antioxidants, a mild heat treatment and packaging were evaluated for changes in physicochemical and sensory properties. It is possible to preserve the grating for four weeks in laminated polythene packages at 5 degrees C in combination with 3% sodium chloride, 0.3% citric acid, 0.009% sodium citrate, 0.02% butylated hydroxyanisole.<br /

Pervious concrete – a sustainable choice in civil engineering and construction

Pervious concrete (no-fines concrete) is a concrete containing little or no fine aggregate; it consists of coarse aggregate and cement paste. It seems pervious concrete would be a natural choice for use in structural applications in this age of ‘green building’. It consumes less raw material than normal concrete (no sand), it provides superior insulation values when used in walls, and through the direct drainage of rainwater, it helps recharge groundwater in pavement applications. The first pervious concrete has been used in Europe and the United Kingdom since 1930s for the building of single story and multistory houses, but had found little acceptance in rest of the world. In recent years, however, due to increased awareness of the need for conservation of nonrenewable mineral resources, increased consideration is being given to the use of pervious concrete in most countries. Even though, it is not yet widely used in Sri Lanka, pervious concrete is generally used for light-duty pavement applications, such as residential streets, parking lots, driveways, sidewalks, channel lining, retaining walls and sound walls. This paper discuss the art of pervious concrete; materials and possible mix proportions, properties such as compressive strength, flexural strength, shrinkage, permeability with initial tests done at Innovation & Application Center of Holcim (Lanka) Limited, and the principal advantages, major disadvantages and principal applications in Sri Lankan construction industry