High Level Of Hardness Research Articles

Multi-Scale Analyses of Three Dimensional Woven Composite 3D Shell With a Cut Out Circle

A composite material are made by combining two or more constituent materials to obtain the desired material properties of each product type. The matrix material which can be polymer and fiber is used as reinforcing material. Currently, the polymer matrix is widely used in many different fields with differently designed structures such as automotive structures and aviation, aerospace, marine, etc. because of their excellent mechanical properties; in addition, they possess the high level of hardness and durability together with a significant reduction in weight compared to traditional materials. However, during design process of structure, there will be many interruptions created for the purpose of assembling the structures together or for many other design purposes. Therefore, when this structure is subject to load-bearing, its failure occurs at these interruptions due to stress concentration. This paper proposes multi-scale modeling and optimization strategies in evaluation of the effectiveness of fiber orientation in an E-glass/Epoxy woven composite 3D shell with circular holes at the center investigated by FEA results. A multi-scale model approach was developed to predict the mechanical behavior of woven composite 3D shell with circular holes at the center with different designs of material and structural parameters. Based on the analysis result of laminae, we have found that the 3D shell with fiber direction of 450 shows the best stress and strain bearing capacity. Thus combining several layers of 450 fiber direction in a multi-layer composite 3D shell reduces the stresses concentrated on the cuts of the structures.

Microstructural analysis, micro-hardness and wear resistance properties of quasicrystalline Al–Cu–Fe coatings on Ti-6Al-4V alloy

The need for engineering components with suitable functionality under harsh wear and aggressive environment subjected to high risk of deterioration, has led to the demand for surface treatment processes and high-performance materials. Ti-6Al-4V is one of the mostly used titanium alloys with more than 70% of the industrial applications in the aerospace, marine and automotive industries. Despite the exceptional properties of Ti-6Al-4V alloy, their low hardness, high susceptibility to corrosion, poor thermal stability and poor tribological properties have limited their viability in the field of engineering. In this research, laser metal deposition technique by incorporating quasicrystalline Al–Cu–Fe coatings can be very beneficial in enhancing the surface properties of Ti-6Al-4V alloy. A 3 kW continuous wave ytterbium laser system (YLS) attached to a KUKA robot which controls the movement of the cladding process was utilized for the fabrication of the coatings. The titanium alloy cladded surfaces were investigated for its microstructure, mechanical and wear resistance properties at different laser processing conditions. The obtained results illustrated that geometrical properties height and width of the deposit increase with an increase in laser power. Increase in scanning speed results in a decrease in the geometrical properties. Ti reacted with increased amount of Al and Fe and less amount of Cu powders to form Al2Ti, Fe0.975Ti, Al0.9Fe3.1Ti0.025 and AlCu2Ti. The optimum performances were obtained for an alloy composition of Ti-6A-4V/Al-Cu-5Fe composite, at laser power of 800 W and scanning speed of 1.0 m min−1. Its performance enhancement compared to the unprotected substrate comprised a significant increase in hardness from 302 to 2740 HV which translates to 89.14% in hardness values above that of the substrate. Coatings with higher hardness levels were achieved mainly due to the larger fraction of hard-intermetallic phases at lower laser scanning speeds. Finally, Ti-6Al-4V/Al-Cu-5Fe coating at laser power of 800 W and scanning speed of 1.0 m min−1 shows the highest wear resistance performance compared to the substrate. Ti-6Al-4V/Al-Cu-5Fe coating was 2.8 times the wear resistance performance of the substrate.

Use of Photocatalysis for Degradation of Glyphosate in Potable Water of CKDu Prevalent Areas

Glyphosate, which is commercially available as Roundup®, was the most widely used herbicide in Sri Lanka until recently. Recent studies report the presence of glyphosate in different water sources (drinking water, surface water, groundwater) in the Chronic Kidney Disease of unknown etiology (CKDu) prevalent areas containing elevated hardness levels. Additionally, WHO studies conducted in 2013, provide evidence of the presence of glyphosate in trace levels in urine samples of CKDu subjects. Thus, glyphosate is suspected to be one of the causal factors for CKDu and its removal, when present in potable water with high hardness levels, is a challenging engineering task. Photocatalysis is recognised to be one of the promising technologies for degradation of glyphosate. Hence, this study focuses on investigating the effectiveness and efficiency of the photocatalysis process for degradation of glyphosate from potable waters containing high hardness levels. Experiments were conducted with high purity Glyphosate and Roundup® in the absence (0 mg/l as CaCO3) and presence of hardness (1,500 mg/l as CaCO3). A sunlight activated water purifier bag available in the market that consists of a Titanium Dioxide membrane was used for application of the photocatalysis process. A 3.0 L water sample containing Glyphosate/Roundup® (glyphosate concentration 1 mg/L) was continuously exposed to sunlight for six (06) hours. A solar irradiance meter was used to measure the sunlight intensity. Samples from the reaction solution were collected at predetermined time intervals and analysed for glyphosate and amninomethyphosphonic acid (AMPA) using GC/MS and LC/MS in the absence and presence of hardness, respectively. A rapid decrease in glyphosate concentration to levels below 0.7 mg/l (USEPA Maximum Contaminant Level) was observed during the first 60 minutes of reaction time under all experimental conditions studied. The concentration of AMPA detected was below the level of quantification in all experiments implying that complete degradation of Glyphosate has occurred until inorganic phosphate is produced. When using high purity glyphosate or Roundup®, slower degradation rates were observed in the presence of hardness compared to that in the absence of hardness. Retardation of glyphosate degradation in the presence of hardness could be attributed to the enhanced persistence of glyphosate due to the formation of glyphosate-Ca and -Mg complexes when hardness is present in water. Similarly, slower degradation rates were observed with Roundup® compared to that of with high purity glyphosate, both in the absence and presence of hardness. The presence of the major adjuvant surfactant [polyethoxylatedtallowamine, (POEA)], which is introduced as an inert ingredient during Roundup® production seems to have enhanced the persistence of glyphosate in water thus causing retardation of Glyphosate degradation by the photocatalysis process. In conclusion, photocatalysis is an effective and efficient technique that could be used to degrade glyphosate in potable water of CKDu prevalent areas in spite of the possible antagonistic effects observed on Glyphosate degradation due to the presence of hardness and/or surfactants. Keywords: CKDu, Glyphosate, Photocatalysis

Performance of Treatment of Oil-Sands Produced Water By Electrocoagulation

In Alberta, Canada, the oil-sands industry plays an important role in the local economy, however the industry is the largest water consumer and has a significant impact on the environment. Only 20% of the available bitumen can be extracted by surface mining, while the rest can be produced by in-situ methods. For in-situ methods, steam is typically injected into the reservoir to reduce the bitumen viscosity, allowing the bitumen to be pumped to the surface along with water. In order to avoid hardness and silica in the produced water from fouling the steam generators, water treatment processes are needed. The treatment of this produced water is challenging as it contains dissolved silica, a high level of hardness and complex organics. Our research has shown that electrocoagulation (EC) is a viable technology to remove a large variety of contaminants. This technology applies the concept of electrochemistry by using sacrificial metal electrodes in an electrochemical cell to produce metal hydroxide coagulants that can efficiently remove contaminants by either adsorption or charge neutralization [1]. In this study, a continuous flow-through cell was designed to remove the contaminants from produced water and synthetic produced water following the same inorganic compositions as the produced water. Mild steel and aluminum were evaluated as electrode materials for the EC treatment process. The results show that EC was very effective for removal of dissolved silica in both real and synthetic produced water. More than 90% of the silica was removed using a charge loading of less than 1000 coulomb of charge per liter of water treated, which corresponds to less than ten minutes of treatment under the experimental conditions used. The effect of design and operating parameters including: water flowrate, current density, dissolved oxygen concentration, and electrode spacing will be reported.

Analysis of Physical Quality and Nutrition of Two Rice Varieties With the Implementation of Various Planting Systems

As an effort to overcome problems in rice cultivation system, it is necessary to use new technologies and innovations. This study aims to determine the physical and nutritional quality of grain and milled rice from 2 varieties of rice using several planting systems. The research was conducted using a Completely Randomized Design of factorial pattern, consisting of 2 factors with 3 replications. The factors were: a) Planting system (S1 = Cubic S2 = Double row 2: 1, and S3 = Twin seed) and b) Rice varieties (V1 = Ciherang; V2 = Inpari 10). The observation parameters include: physical quality of grain, rice milled quality, physical quality of rice and rice nutrition. The results showed that the cubic planting system produced a higher empty grains than the double row and twin seed planting system. The twin seed planting system, yielding lime green grains and yellow broken grains lower than other planting systems, both on rice varieties of Ciherang and Inpari 10. Grains from Ciherang variety had a thinner shell and a higher hardness level of rice compared to grain of Inpari 10 variety, resulting in higher milled rice and head rice, but lower in broken rice and rice groats contents. It can be concluded that: a) the physical quality of rice was not affected by the planting system, but it was significantly affected by the rice varieties; b) the planting system and rice varieties used in this study did not have significant effect on the nutritional quality of the rice produced.

Occurrence of geogenic contaminants in private wells from a crystalline bedrock aquifer in western Quebec, Canada: Geochemical sources and health risks

Nineteen private wells were investigated in order to evaluate the groundwater quality and the issues associated with well water use in a fractured metasedimentary aquifer of the Canadian Shield, in western Quebec (Canada). Groundwater sampling and analysis reveal that the quality of well water is both a potential aesthetic and health concern for the residents. Aesthetic problems are mainly related to the high levels of hardness and dissolved iron and manganese. Potential health risks are associated with the occurrence of brackish groundwater, high manganese concentrations, and arsenic concentrations exceeding the Canadian guideline value of 10 µg/l. Brackish groundwater is suspected to be derived from the mixing of fresh groundwaters with deep calcium-sodium-chloride brines of the Canadian Shield. The occurrences of iron, manganese and arsenic, primarily derived from the natural weathering of bedrock, are highly dependent on the geochemical conditions in groundwater, particularly the redox potential. Arsenic occurs mainly as arsenite (As(III)) and is thought to be released by the dissolution of iron and manganese oxyhydroxides under reducing conditions. Information obtained from well owners indicates that most households use ion exchange water softeners to minimize aesthetic problems of excessive hardness and dissolved iron and manganese concentrations. Homeowners generally take protective measures to reduce their exposure to arsenic when they are aware of the contamination. The exposure to arsenic and manganese may pose health risks for residents that do not take protective measures. The quality of well water is of paramount importance for human health in rural areas. Information on the contaminant sources and individual mitigation measures is essential to assess the health risks associated with groundwater consumption and to ensure the protection of public health.

Reminova and EAER: Keeping Enamel Whole through Caries Remineralization.

This article aims to outline the early development of a King's College London dental spinout company, Reminova, formed to commercialize a novel clinical method of caries remineralization: electrically accelerated and enhanced remineralization (EAER). This method is being developed to address the unmet clinical need identified by modern caries management strategies to keep enamel "whole" through remineralization of clinical caries as a form of nonoperative caries treatment for initial-stage and moderate lesions. A progressive movement within dentistry is shifting away from the restorative-only model, which, it is suggested, has failed. The high prevalence of initial-stage caries across populations provides a significant opportunity to prevent restorations and reduce repeat restorations over a patient's lifetime. Reminova has set out to provide a method to repair lesions without drilling, filling, pain, or injections. The article outlines the rationale for and the chronological stages of the technology and company development. It then outlines corroborative evidence to show that EAER treatment can, in this preliminary in vitro investigation, remineralize clinically significant caries throughout the depth of the lesion as measured by Knoop microhardness and corroborated by scanning electron microscopy. Furthermore, the presented data show that EAER-treated enamel is harder than the healthy enamel measured nearby in each sample and is very similar in appearance to healthy enamel from the subjective interpretation made possible by scanning electron microscopy imagery. The data presented also show that this more "complete" remineralization to a high hardness level has been achieved with 2 remineralizing agents via in vitro human tooth samples. The broad clinical potential of this new treatment methodology seems to be very encouraging from these results. Reminova will strive to continue its mission, to ensure that, in the future, dental teams will not need to drill holes for the treatment of initial-stage and moderate caries lesions.

Geochemistry, Hydraulic Connectivity and Quality Appraisal of Multilayered Groundwater in the Hongdunzi Coal Mine, Northwest China

This study assessed the geochemistry and quality of groundwater in the Hongdunzi coal mining area in northwest China and investigated the mechanisms governing its hydrogeochemistry and the hydraulic connectivity between adjacent aquifers. Thirty-four groundwater samples were collected for physicochemical analyses and bivariate analyses were used to investigate groundwater quality evolution. The groundwater in the mine was determined to be neutral to slightly alkaline, with high levels of salinity and hardness; most samples were of SO4·Cl–Na type. Fluoride and nitrate pollution in the confined aquifers were identified, primarily sourced from coals. Natural geochemical processes, such as mineral dissolution, cation exchange, and groundwater evaporation, largely control groundwater chemistry. Anthropogenic inputs from agricultural and mining activities were also identified in both shallow unconfined aquifers and the deeper confined aquifers, respectively. It was determined that the middle confined aquifer has a high hydraulic connectivity with the lower coal-bearing aquifer due to developed fractures. Careful management of the overlying aquifers is required to avoid mine water inrush geohazards and groundwater quality deterioration. The groundwater in the mining area is generally of poor quality, and is unsuitable for direct human consumption or irrigation. Na+, SO42−, Cl−, F−, TH, TDS, NO3−, and CODMn are the major factors responsible for the poor quality of the phreatic water, while Na+, SO42−, F−, and TDS are the major constituents affecting the confined groundwater quality. This study is beneficial for understanding the impacts of coal mine development on groundwater quality, and safeguarding sustainable mining in arid areas.

Study of Groundwater in Northeast Cairo Area, Egypt

This paper presents a comprehensive hydrogeologic view of the Quaternary aquifer in north eastern Cairo area, Egypt. The hydrogeologic, hydrochemical and isotopic features of the aquifer are determined to assess the groundwater geochemistry and quality for different uses. The groundwater in the aquifer is shallow and flows towards the heavily pumping areas (cultivated and industrial areas). The concentrations of total dissolved solids (TDS) vary considerably in the aquifer, ranging from 225.6 mg/L to 1219 mg/L. Wide variations in the concentrations of major ions, trace elements, nitrate, δ18O and δ2H are detected, indicating the variation in the geologic and recharge conditions. This further indicates the effect of natural processes (weathering, dissolution and ion exchange) as well as anthropogenic activities on the quality of groundwater. Moderate levels of contamination with nitrate, aluminum and manganese are recorded in the groundwater below the cultivated area. The contamination is linked to the extensive use of fertilizers for agriculture and the leakage of wastewater from improper sewage system. The computed nitrate pollution index reveals that about 69.69% of groundwater is safe for drinking, while the rest of groundwater is unsuitable. The calculated water quality index indicates that about 78.79% of groundwater is safe for human consumption and the rest of groundwater is poor for consumption because of the contamination with the high levels of manganese, total hardness, pH, sulphate, aluminum, and nitrate. The contaminated groundwater needs to be treated before consumption. Hence, periodic groundwater quality checks are recommended.

Perspectives on impacts of water quality on agriculture and community well-being-a key informant study from Sri Lanka.

Integrated management of water quality is critical for sustaining food production and achieving overall well-being of a community. Further, understanding people's perceptions and engagement can play an important role in achieving water and food security. The main aim of this study was to investigate the perspectives of community and other stakeholders as to how water quality impacts on agriculture, livelihood and community well-being within rural farming communities of two dry zone districts of Sri Lanka. The study adopted 'key informant interviews' as the methodology to investigate community and other stakeholder perspectives to collect primary data over a period of four months. The interview contents were then examined using a frequency matrix and graphed using an Excel graphing tool. The raw text was also analysed to understand the broader patterns in the text. A fuzzy logic cognitive map (FCM) was developed using the relationships between various concepts and linkages provided by the key informants. All key informants were concerned with the quality of drinking water they consume and the water used for their food preparation. Key informants representing the farming community indicated that the use of poor quality groundwater with higher levels of hardness has made growing crops difficult in the region. The key informants also identified extensive and ongoing use of agro-chemicals and fertilisers as a major source of pollution in water bodies in both spatio-temporal scale. Based on key informant interviews, possible initiatives that can help improve surface water and groundwater qualities for both drinking and agricultural use in the dry zone of Sri Lanka can be categorised into four broader themes, viz., provision of filtering/treatment systems, reduction in the use of agro-chemical and fertilisers, education of community stakeholders and support of alternative options for portable water supplies. The study indicates that in the key informants' view of groundwater and surface waters' continued deterioration in the absence of a proper governance structure, a majority of farmers will have restricted access to good quality water to meet daily and agricultural needs, and this will affect the health of the elderly and children in the area. Further, a majority of key informants were of the view that management of surface water and groundwater should be a shared responsibility between the government and the community in the region and appropriate policy initiatives that will improve water literacy at all levels are mandatory to address future water quality challenges.

Comparative Study on Microscopic, Physical and Mechanical Properties of Conventional and Spark Plasma Sintered Nano-TiO2-Dispersed Zirconium-Based Alloys

In this study, nano-TiO2 (1.0–2.0 wt.%)-dispersed Zr-based alloys with nominal compositions: 45Zr–30Fe–20Ni–5Mo (alloy 1), 44Zr–30Fe–20Ni–5Mo–1TiO2 (alloy 2) and 44Zr–30Fe–20Ni–4Mo–2TiO2 (alloy 3) are synthesized by mechanical alloying in a dual-drive planetary ball mill followed by powder consolidation with conventional sintering at 1400 °C/spark plasma sintering at 900–1000 °C. For microstructural and phase analysis of mechanically alloyed powders and consolidated products, XRD, SEM/EDS and TEM studies were carried out. Density measurement and mechanical property (compressive strength, hardness and wear) characterization were also carried out. X-ray diffraction and TEM analysis reveal formation of different intermetallics of 10–30 nm size along with TiO2 (10–20 nm) throughout the matrix of the consolidated samples. Alloys consolidated by spark plasma sintering displayed high levels of compressive strength (825–1240 MPa) and hardness (10.38–16.85 GPa) which was 1.5–2 times higher than that was obtained in conventional sintering. Addition of TiO2 helps in enhancement of mechanical properties, and effect was more prominent with 2.0 wt.% TiO2.

Developing of Mechanical Properties for Reinforcing Bar Steel through Heat Treating with Various Cooling Media

In this study, mechanical properties development of reinforcing bar steel (rebar) has examined through heat treatment process. This rebar was made from low carbon lateritic steel with the small amount of alloying elements Cr,Mn and Ni. There were 4 rebar steel samples that consisted of rebar steel was applied hot rolled at 1200 °C at the beginning process in factory (sample A) and three others were conducted by quenching (sample B, C and D). The various of cooling media such as water (sample B), oil (sample C) and air (sample D) have applied to obtain different microstructure behavior and also mechanical properties. Initial heating was conducted to B,C and D rebar specimens at the austenitizing temperature (950 °C) for 1 h and followed by quenching. The experimental results showed that water quench exhibited of higher hardness level (50,26 HRC) for rebar steel but decreasing in toughness (34 Joule) and elongation (4%) than as cast because of martensite phase formed. Sample C showed that martensite and the small amount of retained austenite with hardness and tensile strength below the sample B, but elongation and energy absorbed were above. The lowest of hardness and tensile strength were obtained from sample D. It was appropriate with microstructuree formed as follows ferrite-pearlite phase and widmanstatten-bainite cluster. Nevertheless, sample D is suitable treatment for tensile strength and elongation requirements rebar standard, there are 558 Mpa and 26% respectively (min. 440 MPa and 20%).

Mitochondrial activity in fern spores of Cyathea costaricensis as an indicator of the impact of land use and water quality in rivers running through cloud forests

Early-warning biomarkers, such as mitochondrial activity, have become a key tool in ecosystem assessment. This study aims to evaluate the response of mitochondrial activity in spores of the autochthonous fern Cyathea costaricensis as a bioassessment tool concurrently with land use and physicochemical evaluation in 11 sites along Bobos River, Veracruz, Mexico, to assess river water quality. Bobos River is located in the Nautla basin, northeastern Veracruz (Mexico); the upper river runs through a protected natural area (Filobobos River and adjacent areas). The study involved three monitoring periods: February, June and September 2014. In each study site, physicochemical water quality parameters were recorded to calculate the Water Quality Index (WQI); also, study sites were characterized in terms of land use. Water samples were collected to perform bioassays where spores of C. costaricensis were exposed to samples to assess mitochondrial activity; a positive control exposure test was run under controlled conditions to maximize mitochondrial activity. A Principal Component Analysis was performed to correlate land-use attributes with environmental variables and mitochondrial activity. Three river sections were identified: the upper portion was characterized by the dominance of native vegetation, the highest WQI (in September), and the lowest mitochondrial activity (63.87%–77.47%), related to the geological nature of the basin and high hardness levels. Mitochondrial activity peaked in September (98.32% ± 9.01), likely resulting from nutrient enrichment in the rainy season, and was lowest in February (74.54% ± 1.60) (p < 0.05). Mitochondrial activity was found to be a good benchmark for the assessment of water quality, reflecting the effects of physicochemical characteristics. Mitochondrial activity showed changes along the river and between seasons, associated with environmental characteristics such as land use and the geological nature of the basin, as well as with those related to human impacts.

Avaliação do abrandamento de água calcária utilizando hidróxido de cálcio e carbonatação

A água é um recurso fundamental para a vida na terra e a sua qualidade define seus diversos usos. A qualidade da água é entendida como resultado das ações antrópicas e da sua interação com o meio físico. Assim a água possui características físicas, químicas e biológicas em virtude de suas propriedades de solvente e de sua capacidade de transportar partículas. Dentre as características químicas está a dureza de carbonatos que representa a concentração de íons como o cálcio e o magnésio em solução. Esses íons estão presentes na água subterrânea através de processos de intemperismo químico que dependem do tempo de contato entre a água e a rocha, temperatura, CO2 disponível e da presença de ácidos orgânicos e inorgânicos. Em níveis elevados de dureza total a água apresenta um sabor diferenciado o que pode ser desagradável ao paladar das pessoas. O objetivo desse trabalho é verificar o abrandamento da concentração dos carbonatos de cálcio e magnésio, pela dissolução de gás carbônico e hidróxido de cálcio, alterando o equilíbrio do sistema carbonato. Foram testadas a água carbonatada, água carbonatada e aerada e a água natural com cinco concentrações de hidróxido de cálcio (0, 25, 50, 75 e 150 mg L-1). O parâmetro avaliado foi a dureza de carbonatos. Os experimentos foram configurados em fatorial com dois fatores, aplicou-se o teste Tukey a um nível de 1% de significância. Os resultados mostraram que o fator água e o fator concentração de hidróxido foram significativos a 1% de significância, já a interação dos dois fatores não. Contudo o melhor resultado na remoção da dureza foi na concentração de 150 mg L-1 de hidróxido de cálcio em água carbonatada e aerada.

The Effects of Transient Temperature around Welds on Mechanical Properties of A36 Steel Plate

There are various ways for welding experts to improve their production quality, and one of which is by designing a particular type of welding tool. Besides aiming to replace the function of operator’s body parts, the tool is also able to control buckling distortions, crack propagations, and stress voltage, as well as to save an additional work, which is the heat treatment after welding process. The best method to control buckling distortions from the thin plate is by applying pre-heating and thermal tensioning. Thermal tensioning is the characterization by heat application during welding process. Transient thermal tensioning is a supporting tool around the weld which is given periodical heat by following the movement of arc welding. The purpose of this research was to minimize distortions and maximize the performance (mechanical properties) of welding joints shaped due to the transient temperature application during the welding process. The method employed in this research was experiment by using A36 steel plate with transient temperature variation of 100, 200, and 300oC, with velocity of 8 mm/s and heater (toutch) distance of 4, 6, and 8 cm. In this research, the researcher conducted tensile-strength test according to the JIS G 3101 standard and hardness test around weld, HAZ (Heat Affected Zone), and parent metal.The findings showed that the change of transient temperature and heater distance affected the mechanical properties (hardness and tensile strength) of A36 steel. The highest level of hardness was obtained in the temperature of 200°C and heater distance of 6 cm, which was as much as 404 VHN. The highest level of tensile strength was obtained in the temperature of 200°C and heater distance variation of 8 cm with yield stress of 302 Mpa and maximum tensile strength of as much as 491 Mpa.

Failure analysis of dissimilar weld in heat exchanger

The failure analysis of a dissimilar weld in a heat exchanger has been conducted. Within hours of being placed in service, the circumferential weld joining the carbon steel shell to the duplex stainless steel tubesheet experienced partial cracking as H2S was being introduced into the exchanger. The cracking of the weld was determined to be associated with sulfide-stress corrosion cracking facilitated by high weld hardness levels and local dilution of chemistry in the weld.

ANALISIS KUANTITATIF KESADAHAN TOTAL AIR MINUM ISI ULANG YANG DIJUAL DI WILAYAH KAYU TANGI KOTA BANJARMASIN

Water is one of the important needs for human body. Therefore, water which consumed should be healthy and have certain quality. One of its quality parameter is total hardness. Total hardness is the hardness which caused by Ca2+ and Mg2+ ions. Hard water, or water with a high level of total hardness, if consumed in long term can lead to hyperparatyroidsm, Nephrolithiasis, and musculusweakness. The aim of this study were to determine total hardness level of refill drinking waterwhich sold in Kayutangi Banjarmasin and to compare it with the standard parameter of total hardness in Permenkes 492/Menkes/IV/2010 which is 500 mg/L in maximum. There were 16 samples in this study that taken from refill drinking water store were found accidentally. The quantitative analysis was done by complexometry titration method with Na2-EDTA as titrant and Eriochrome Black T as indicator. The results showed that the ranges of total hardness level of 16 samples that determined between 35,64 – 99,00 mg/L which is suitable with the standard based on Permenkes 492/Menkes/IV/2010

Scanning electron microscopy study of hair shaft changes related to hardness of water.

Brittleness and breakage of hair is a common complaint in the geographical area of Saudi Arabia where we work. This area has a high level of hardness in normal tap water. We aimed to study and compare structural differences and relative deposition of calcium and magnesium salts on the hair shaft surface using scanning electron microscopy (SEM) between hair shaft samples from normal, healthy volunteers treated with hard and soft water. Hair samples obtained from 20 healthy volunteers were divided into two groups. One group was treated with hard water for 3 weeks and the second with soft water for the same duration. SEM was used to assess hair shaft surface damages and relative deposition of calcium and magnesium on the surface of the hair. There was no statistically significant difference between the study and control group as far as surface changes under SEM were concerned. As far as the relative deposition of calcium and magnesium was concerned, there was no statistically significant difference in calcium deposition between the control and study samples (P = 0.28). On the other hand, magnesium deposition showed a significant difference between both groups (P = 0.001), with a higher level in samples washed with hard water. Hard water may be associated with increased deposits on the hair shaft surface, however, this does not necessarily translate into evident structural surface changes, as evidenced by SEM.

Fluorinated zirconia-based sol-gel hybrid coatings on polycarbonate with high durability and improved scratch resistance

Hard, scratch-resistant and transparent fluoropolymer-based hybrid coatings are successfully prepared through the sol-gel chemistry and investigated, in the attempt to correlate the chemical, physical and surface properties of these materials with the mechanical properties (i.e. hardness and elastic modulus) measured at the nanoscale by atomic force microscopy (AFM). The organic component of these coatings consists in a hydroxyl-functional fluoropolymer resin, which belongs to the class of chlorotrifluoroethylene-vinylether copolymers and exhibits remarkable properties such as easy handling, great weather resistance, good adhesion and flexibility of coatings. A functionalization of this copolymer is also performed using an isocyanate-functionalized silane in order to assure a covalent cross-linking of organic fluorinated resin with inorganic phases. The combination of the silanized chlorotrifluoroethylene-vinylether copolymer with different sols composed of silica and zirconia is used to obtain high scratch resistance and high durability coatings on polycarbonate. A series of three hybrid coatings with different zirconia/silica molar ratios (0.09/0.48) are developed and analyzed by differential scanning calorimetry (DSC), water contact angle measurements, pencil hardness and adhesion tests. AFM scratch hardness, coating wettability and surface composition measured by Fourier transform infrared spectroscopy (FTIR) are regularly monitored over long-term UV–vis light exposure, to assess the durability of the hybrid coatings. Interestingly, the hybrid fluorinated coatings exhibit an improved scratch resistance and a superior long-term stability when exposed to an accelerated weathering, compared to pristine PC substrates. The mixed silica/zirconia hybrid coatings with a low and intermediate zirconia-to-silica ratio also show excellent mechanical strength, high level of hardness and superior integrity after long-term light exposure.

Research into ion exchange softening of highly mineralized waters

Very often in the processes of water purification it is required to apply the processes of water desalting and conditioning. Their use is predetermined by the increased mineralization and high level of hardness of surface sources of water consumption. It is expedient to use methods of ion exchange for purification of these waters. We present the results of research into ion exchange softening of highly mineralized waters on weak­ and strong acidic cationites. It is demonstrated that with the increase in the content of sodium ions in water, total exchanging dynamic capacity of strong acidic cationite KU­2­8 is reduced from 1744 to 1295 mg­eqv/dm 3 . This decrease in efficiency of the sorption of hardness ions is due to the increasing degree of desorption of calcium and magnesium ions at high concentrations of sodium ions. We defined conditions of softening highly mineralized solutions on weak acidic cationite Dowex Mac­3 in the Na + form and it was shown that the efficiency of softening of these solutions depends little on the concentration of sodium ions. It was found that this cationite in the Na + form is capable to absorb the hardness ions under those conditions when, in the case of strong acidic cationite KU­2­8, their desorption occurs. We defined conditions of consistent regeneration of strong­ and weak acidic cationites by the solutions of acids. In this case, the solutions after regeneration of strong acidic cationite were further used for regeneration of weak acidic cationite. When carrying out such regeneration, almost total desorption of the hardness ions was achieved from both strong­ and weak acidic cationite.