In this study, hydrophobic silica layers were synthesized through the sol–gel method derived from the silica precursor, methyltriethoxysilane (MTES), at various pH and calcination temperatures. ...Coating silica on ceramic plates significantly increases the surface hydrophobicity of the ceramic plates. The increment in hydrophobicity comes from the surface roughness and the hydrophobic group –CH
3
derived from MTES. Increasing pH causes the hydrophobicity of the silica film to escalate. In the MTES silica film calcined at 350 °C, a change in pH from 1.97 to 9.66 enhanced the water contact angle from 92° to 120°, while increasing the calcination temperature decreased surface hydrophobicity. MTES silica film can maintain hydrophobic properties up to 420 °C. Mid pH (approx. 4.66) yields the silica material with the highest thermal stability. Gas sorption analysis shows that the resulting material has low porosity, surface area, and pore volume.
Nickel (II)–alizarin red S (Ni–ARS) complexes were synthesized using different mole ratios and pH. This study aims to analyze the effect of mole ratio and pH on the resulting complex structure and to ...determine the relationship between the geometric stability of the complex structure and its antibacterial ability using molecular docking studies. The variation in moles (1:2 and 1:3) did not affect the type or structure of the complex produced, but variations in pH affected the type of complex obtained. The dimer complex was obtained at pH 7 and 8, while the monomer complex was obtained at pH 6. ARS ligand complexation occurred in the carbonyl and hydroxyl (peri-hydroxy carbonyl) groups. DFT studies show that monomeric complexes are more stable than dimeric complexes while confirming a higher yield of monomeric complexes than dimeric complexes. Although DFT calculations show that monomer complexes are more stable than dimers, molecular docking showed antibacterial activity of
E. coli
and
S. aureus
from dimer complexes > monomer complexes > ARS. This study concluded that geometric stability is not always directly proportional to its bioactivity ability.
Bismuth oxide has been considered as a promising electrode material due to the high theoretical capacity, low cost, and non-toxic nature. However, its application has been limited by the low ...electrical conductivity. In this work, bismuth oxide/commercial activated carbon composite were successfully synthesized through hydrothermal method. Bismuth nitrate pentahydrate with concentrations of 8, 24, and 32 mmol were mixed with Na
SO
, NaOH, and commercial activated carbon. The mixture was then put into a hydrothermal reactor and heated at 110°C for 5 h. These composite materials can have a 10
–10
higher electrical conductivity, depending on the bismuth oxide ratio, compared to both bismuth oxide and commercial AC separately.
This study aims to provide an overview of the unique going concern strategy of Tokang pandhih Jokotole (read: SMEs blacksmith) which produces patterned sickles so that these MSMEs are able to survive ...and even have been traversed by several generations. This study used a configurative ideographic studies case study approach to analyze the data. The conclusion of this study is that Haji Masduri implements a strategy to maintain product quality to maintain customer trust. The development of a business into a business that has a business license with the “Jokotole” brand is a government facility that is accepted by Haji Masduri. In business operational management, Haji Masduri carries out a specialization strategy for production work, a gratuity system (profit sharing) based on the selling price of patterned sickle workers, and "utilizing the network" owned to obtain quality raw materials without leaving the house (place of business). The strategy for maintaining cash flow carried out by Haji Masduri is the production system for orders and a 50% down payment. The impact of the maintained product quality, Haji Masduri can apply a strategy to determine the selling price without the bargaining process of ordering a patterned sickle.Keywords: Business Strategy; Going Concern; SMEs; Cultural Products. AbstrakPenelitian ini bertujuan untuk memberikan gambaran keunikan strategi going concern pandai besi tokang pandhih Jokotole yang memproduksi celurit bermotif sehingga UMKM ini mampu bertahan bahkan sudah dijalan oleh beberapa generasi. Penelitian ini menggunakan pendekatan studi kasus configurative ideographic studies untuk menganalisis data. Simpulan penelitian ini adalah Haji Masduri menerapkan strategi menjaga kualitas produk untuk menjaga kepercayaan pelanggan. Pengembangan usaha menjadi usaha yang memiliki ijin usaha dengan brand “Jokotole” adalah fasilitas Pemerintah yang diterima Haji Masduri. Setelah memiliki ijin usaha, Haji Masduri dapat mengakses lebih banyak fasilitas dari Pemerintah. Dalam manajemen operasional bisnis Haji Masduri menjalankan strategi spesialisasi kerja bagian produksi, sistem upah persenan (bagi hasil) berdasarkan harga jual pada tenaga kerja celurit bermotif, dan “memanfaatkan jaringan” yang dimiliki untuk memperoleh bahan baku ayng berkualitas tanpa meninggalkan rumah (tempat usaha). Strategi menjaga cash flow yang dilakukan oleh Haji Masduri adalah dengan sistem produksi pesanan dan uang muka 50%. Dampak dari kualitas produk yang terjaga, Haji Masduri dapat menerapkan strategi penentuan harga jual tanpa proses tawar menawar dari pemesan celurit bermotif. Kata Kunci: Strategi Bisnis; Going Concern; UMKM; Produk Budaya.
Bamboo, a fast-growing plant from Asia, is used as building material with unique properties, while exhibiting fast degradation due to its hydrophobicity. Therefore, many attempts have been ...implemented using several technologies for bamboo modification to alter the hydrophobicity. Most previous studies producing superhydrophobic properties are conducted by using tetraethoxysilane (TEOS) as a precursor agent. However, this method, using TEOS with harmful properties and unaffordable compounds, requires many steps to accomplish the experimental method. Therefore, this paper employed geothermal solid waste as a silica source of the precursor. Thus, an effective and efficient method was applied to prepare superhydrophobic coating by using a precursor of geothermal silica and further modification using hexamethyldisilazane (HMDS) and trimethylchlorosilane (TMCS). The research was executed by the full factorial statistical method using two numerical variables (HMDS/TMCS concentration and silica concentration) and one categorical variable (solvent types). The uncoated material revealed higher weight gain in mass and moisture content than that of the coated bamboo after the soil burial test to assess the durability of the bamboo. However, the durability of superhydrophobic coating realized hydrophobic performance for both agents during sand abrasion for a total of 120 s at an angle of 45°. Statistical results showed the optimum contact angle (CA) achieved in superhydrophobic performance with lower silica concentration for HMDS concentration and the appropriate solvent of n-hexane for HMDS and iso-octane for TMCS. All results were supported using many instruments of analysis to confirm the step-by-step alteration of geothermal silica to be used as a superhydrophobic coating, such as XRF, XRD, FTIR, SEM, and SEM EDX.
Synthesis and preparation of carbon membranes have been carried out and applied for desalination. Carbon is obtained from sucrose by pyrolyzing at various temperatures. Carbon membranes are made by ...coating alumina tubes with sucrose solution using dip-coating. The effect of carbonization temperature on the character of the membrane material and the desalination performance was investigated. This study’s results indicate that the carbonization temperature modifies the characteristics of membrane material. TGA data show that solid sucrose is thermally stable up to 210°C. This result aligns with the FTIR results, which show that functional group changes occur when the carbonization temperature exceeds 200°C. The GSA data shows that the resulting adsorption isotherm is type V, indicating mesoporous material. However, the volume and pore size of the carbon membrane material is minimal. SEM results show that carbon is dense but not equitably distributed. The salt rejection reached 100%, and the water flux was greater than 10 kg.m
−2
.h
−1
at a feed concentration of 1% and a temperature of 60°C. Salt rejection is consistent at around 100% for up to 60 h for long-term testing. The absence of significant alterations indicates the high stability of the carbon membrane.
This work investigates the preparation, characterisation and performance of binary iron/cobalt oxide silica membranes by sol–gel synthesis using tetraethyl orthosilicate as the silica precursor, and ...cobalt and iron nitrates. It was found that cobalt and iron oxides were generally dispersed homogeneously in the silica structure, with the exception of a few minor patches rich in cobalt oxide. The sol–gel synthesis affected the micro-structural formation of binary metal oxide silica matrices. Increasing the iron content favoured condensation reactions and the formation of siloxane bridges, and consequently larger average pore sizes which lead to low He/N2 permselectivity values below 20. In the case of high cobalt content, a higher silanol to siloxane ratio was observed with tighter pore size tailoring, as evidenced by higher He/N2 permselectivities reaching 170. The binary metal oxide and silica interfaces proved to follow a molecular sieving mechanism characterised by activated transport where the permeance of the smaller gas molecules (He and H2) increased with temperature up to 500°C, whilst the permeance of larger gas molecules (CO2 and N2) decreased.
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•Binary iron cobalt silica membrane prepared via a sol–gel method.•Fe content favoured condensation reactions and siloxane bridges.•Co content inhibited condensation and favoured the formation of silanols.•Best performance for silica membranes with low Fe and high Co content.
Research on synthesis of bismuth oxide (Bi2O3) using sol-gel method with varying calcination temperatures at 500, 600, and 700 °C has been done. This study aims to determine the effect of calcination ...temperature on the characteristics of the obtained products which encompasses crystal structure, surface morphology, band-gap energy, and photocatalytic activity for the decolorization of methyl orange dyes through its kinetic study. Bismuth oxide prepared by sol-gel method was undertaken by dissolving Bi(NO3)3·5H2O and citric acid in HNO3. The mixture was stirred then heated at 100 °C. The gel formed was dried in the oven and then calcined at 500, 600, and 700 °C for 5 h. The obtained products were a pale yellow powder, indicating the formation of bismuth oxide. This is confirmed by the existence of Bi–O and Bi–O–Bi functional groups through FTIR analysis. All three products possess the same mixed crystal structures of α-Bi2O3 (monoclinic) and γ-Bi2O3 (body center cubic), but their morphologies and band gap values are different. The higher the calcination temperature, the larger the particle size and the smaller the band gap value. The accumulative differences in characteristics appoint SG700 to have the highest photocatalytic activity compared to SG600 and SG500 as indicated by its percent degradation value and decolorization rate constant.
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