Evaluation of soil replacement and cement grout injection in soil settlement

This paper discusses the process of original soil stabilization in Trans Sumatra Bakauheni-Terbanggi Besar Toll Road Project Package 2 Sidomulyo-Kotabaru. The soil replacement process was conducted at approximately 24 kilometres along the toll’s main road. The original soil bearing capacity analysis stage was by performing a Dynamic Cone Penetrometer (DCP) and Sondir test to analyze the deep of hard soil. A soil replacement was carried out to replace the original soil with soil that has appropriate specification. the piling up process was conducted in stages, which has Sandstone in such of the layer. The research done about the landfill sample was retaken and collected at 68 points. The stockpile soil samples collection was then followed by the analysis which was conducted in the laboratory to find the soil bearing capacity. There are 4 types of bearing capacity parameters analyzed, namely specific gravity, water content, aggregate analysis (Sieve Analysis), and consistency limit (Atterberg Limit). Referring to it, then there was the classification of soil types according to AASHTO M145 & Casagrande Soil Classification System. A point that has settlement after soil replacement is STA 52+000. So, there need to add soil stabilization, that is cement grout injection. Researchers analyzed the soil settlement by interpretation method. Results showed that soil replacement and cement grout injection could decrease a soil settlement by about 15.07 cm to become 0.93 cm.

Air quality analysis through measurement of pb levels in blood using atomic absorption spectrophotometer

Air pollution is a problem that needs attention, especially pollution by heavy metals such as lead (Pb). This research was conducted to measure the levels of Pb in the blood of people who do a lot of daily activities on the highway in the Ulaanbaatar region, Mongolia, so that an overview of the level of exposure to Pb in the air is obtained. The study was conducted using an observational method by measuring the blood directly from the participants using an atomic absorption spectrophotometer. The participants involved were 20 people who met the criteria. The results showed that the average level of Pb in the blood of people who had daily activities on the highway was 8.97 ppm. Where the smallest level is 5.12 ppm and the highest level is 12.06 ppm. This value is far above the threshold value determined by WHO, which is 0.05 ppm. Therefore, it can be concluded that the air quality in the Ulaanbaatar area is in the poor category with a high level of Pb exposure.

Development and validation of chemistry learning videos as learning media in the era of the COVID-19 pandemic

Learning media, especially videos, are very effective in achieving learning objectives, especially during the COVID-19 pandemic. Therefore, this study aims to develop learning videos as learning media during the COVID-19 pandemic. The research was conducted using a development research approach from the Borg & Gall model. The developed product has good validity. Where the results of the content validation test by material experts show the CVR value in the range 0.75 – 0.95 (above the critical CVR value). The construct validity test results have a value in the range 0.75 – 0.95 so that it is included in the valid category. And lastly, the test results for student responses have percentage values in the range of 79% - 89% so that they are included in the interesting and very interesting category. Based on these results, the developed learning video can be used as a learning media solution during the COVID-19 pandemic.

Induction of Rhizoctonia resistance to odontoglossum ringspot virus (ORSV) infection on orchid leaf organ viability

Orchid plants are in great demand by the public as ornamental plants that have economic value and the beauty of attractive flower shapes and colors, especially Phalaenopsis and Dendrobium. Related to this, conservation efforts are needed through cultivation. However, these efforts are often hampered by viral infections. One of the viruses that trigger inhibition of orchid cultivation that often appears is ORSV. Control efforts that are relatively safe and efficient can utilize mycorrhizae in orchids which play a role in increasing the absorption of plant nutrients. The use of Phalaenopsis and Dendrobium with the induction of Rhizoctonia sp. against ORSV is a very important alternative biofertilizer and biocontrol agent. The objectives of this study were 1) to determine the effectiveness of orchids induced by Rhizoctonia resistance, 2) to determine the viability of orchid leaf organs to ORSV infection, 3) to determine the viability of orchid root organs resulting from Rhizoctonia resistance to ORSV infection. This study was conducted in January 2021 – March 2021 at the Botanical 2 Laboratory, Department of Biology, Faculty of Mathematics and Natural Sciences, University of Lampung. This study employed a completely randomized factorial with 6 treatments and 4 replications. The variable observed in this study was the effectiveness of mycorrhizae, leaf and root length, number of leaves and roots, and leaf width. The data obtained were homogenized using Levene's test and then analyzed by ANOVA and Tukey's further test at the 5% level. The results showed that the effectiveness of mycorrhizae occurred on the 3rd day of incubation. In leaf organs, Phalaenopsis amabilis showed an increased response and Dendrobium discolour showed a decreased response in leaf length, width, and number. Meanwhile, in the root organ, Dendrobium discolour showed an increased response and Phalaenopsis amabilis showed a decreased response in root length and number of roots.

Various ORSV infection symptoms on ceratorhiza induction in orchid plants

Several types of orchids that are in great demand and cultivated by various groups are Phalaenopsis sp. and Dendrobium sp. Mycorrhizae are needed by orchid plants to complete their life cycle. This is because mycorrhizae are capable of symbiosis with the root system of the host plant so that the plant's capacity to absorb elements will increase. This study aims to determine the extent to which Ceratorhiza induction on Phalaenopsis amabilis and Dendrobium discolour orchids can suppress the symptoms of Odontoglossum ringspot virus (ORSV) infection. The method used in this study was a factorial completely randomized design (CRD) with 2 factors and 4 replications. The first factor is the type of orchid used, namely Phalaenopsis amabilis (A1) and Dendrobium discolour (A2), while the second factor is the type of administration of mycorrhizae, viruses, and mycorrhizal viruses. Observation of disease symptoms is done by looking at the symptoms that appear on leaves that have been infected with ORSV. The results showed that the symptoms that appeared in Phalaenopsis amabilis were in the form of mosaic, necrosis, leaf malformation, while in Dendrobium discolour were mosaic and necrotic. Ceratorhiza was not able to suppress the symptoms of disease infection because based on the results obtained; the treatment on orchids inoculated with mycorrhizae and viruses showed more severe symptoms compared to the treatment only inoculated with viruses increased response and Dendrobium discolours showed a decreased response in leaf length, width, and number. Meanwhile, in the root organ, Dendrobium discolour showed an increased response and Phalaenopsis amabilis showed a decreased response in root length and number of roots.

Analysis of formaldehyde content in salted fish at Ciroyom market, Bandung City, Indonesia

Salted fish is one of the processed fish products that are in great demand by the people of Indonesia. This type of preparation has good durability with natural processes. However, there are some cases that use chemicals as preservatives, such as formaldehyde. This study aims to determine the formaldehyde content in salted fish that is traded in the market in Indonesia. This research is descriptive and the sample is taken from Ciroyom Market, Bandung City, Indonesia, randomly. Samples were analyzed qualitatively to observe the physical characteristics of salted fish. In addition, quantitative analysis was also carried out to determine the level of formaldehyde present in salted fish using a UV-Vis spectrophotometer at a wavelength of 520 nm. The results of the analysis showed that 4 of the 15 samples tested contained formaldehyde with a concentration of 0.033 – 0.482 ppm. The characteristics of these samples physically also have similarities with the characteristics of fish containing formaldehyde, namely bright white and hard textured.

Identification of borax in meatballs at Ciroyom Market, Bandung City, Indonesia

Borax is a chemical substance that is prohibited from being used as a food additive because of its toxic nature. However, the use of borax is still widely found, one of which is meatballs the most. This study aims to identify the borax content in meatballs. Samples were taken from Ciroyom Market, Bandung City, Indonesia using total sampling and obtained as many as 10 samples of meatballs. The samples were analyzed qualitatively by observing physical conditions and testing using BaCl2 solution. Meanwhile, quantitative analysis was carried out using a UV-Vis spectrophotometer at a wavelength of 428 nm. The results of the analysis showed that all samples were indicated to contain borax. Even the quantitative test using UV-Vis spectrophotometer showed that the highest borax content was found in sample 10, which was 3.672,9 µg/ml.

The seepage flow analysis of main dam stability in Way Sekampung dam development project

Analysis using depression line method was conducted in two conditions, at normal water level (± 124 m) with a result of 1.11 × 10-3 m3/s and at flood water level ± 126.5 m with result 1.33 × 10-3 m3/s. Capacity shows (< 1%) the average enters the reservoir, making it safe from the danger of distress. Safety calculations for pipping showed a bigger value than the filtration flow speed indication at the average value of 4,638 ( > 4) which means that dam will not make pipping symptoms. Analysis conducted on the slope of the dam using slice method without entering the value of seismic coefficient obtained a safe number result in all loading conditions and the analysis by adding a seismic coefficient get a safe result except in two conditions, at elevation ± 126.5 m is SF 1.05 and at elevation ± 124 m SF is 1.05.

Variation of resistance response of orchids induced by Rhizoctonia against the infection of Odontoglossum ringspot virus (ORSV) based on percentage of disease development

Orchid is one of the largest groups of flowering plants that are in great demand by society. Besides, the various flowers with a long vase life, the price of orchids is also stable and affordable. Phalaenopsis and Dendrobium are the most popular types of orchids. To anticipate this, orchid cultivation needs to be improved. However, orchid cultivation is not always accompanied by the effort of disease prevention, particularly those caused by viruses. The virus that most infects orchids is the Odontoglossum ringspot virus (ORSV). Symptoms that appear on the leaves are chlorosis, mosaic with a pattern of lines, circles, and necrotic rings/rings. Control of viral infections can utilize organisms that are able to induce resistance, namely mycorrhizae. Mycorrhizae will penetrate into the root cortex tissue and provide nutrients for the orchid. Mycorrhizae that are quite often found are Rhizoctonia and are applied by induction to orchids. Induction was undertaken by planting orchids in Rhizoctonia inoculum until anatomically a peloton structure (solid coils) was formed on the orchid roots. The aim of this study was to study the response of orchid plants in the form of percentage incidence and intensity of the disease and the level of plant resistance to ORSV infection in Phalaenopsis amabilis and Dendrobium discolour which had been induced by Rhizoctonia. This research was conducted at the Laboratory of Botany, Biology, FMIPA, Universitas Lampung, using a factorial completely randomized design (CRD). Factor 1 was the type of orchid and factor 2 was mycorrhizal induction, virus inoculation, and a combination of both with 4 replications. The finding indicated that Phalaenopsis amabilis was more susceptible to ORSV infection than Dendrobium discolour based on a higher incidence and intensity of the disease. Mycorrhizal induction and virus inoculation (MAV) in Dendrobium discolour showed an increase of resistance response compared to Phalaenopsis amabilis.

Analysis of chromium(IV) levels in residents' well water around the Citarum River, Indonesia

Wells as a source of water that is commonly used by people in Indonesia are very dependent on the conditions of the surrounding environment. The presence of environmental pollution by waste will be very dangerous, especially if the waste contains heavy metals such as Cr(VI). The highly soluble nature of Cr(VI) allows the process of infiltration from the river into the well water. This study aims to analyze the content of Cr(VI) in the well water of residents around the Citarum River. Samples were taken from two areas that have the criteria for the level of pollution and the environment which is dense with industrial activity, with a total of ten wells spread over the area. The concentration measurement was carried out using an atomic absorption spectrophotometer at a wavelength of 357.9 nm. The results showed that the levels of Cr(VI) ion at Location 1 were in the range of 0.014 – 0.022 ppm so that it could still be used for daily activities because it was below the threshold value. At Location 2, there are six wells whose water is still suitable for use because the value of the Cr(VI) ion content is still below the threshold value. Meanwhile, the water in the other four wells contains Cr(VI) ion level that exceeds the threshold value, so it can be said that it is not suitable for daily use.