Chemical Stripping Research Articles

A cross-sectional study on urogenital schistosomiasis in children; haematuria and proteinuria as diagnostic indicators in an endemic rural area of Nigeria.

Rapid and accurate diagnosis is necessary for the management of schistosomiasis in endemic areas. To assess the burden of urogenital schistosomiasis and the diagnostic efficiency of morbidity indicators of the disease in an endemic rural community of Nigeria. A cross-sectional school-based study was conducted. Urine samples of 487 pupils were screened microscopically for S. haematobium and tested for haematuria and proteinuria using chemical reagent strips. The prevalence and intensity of infection were 57.1% and 45.0 eggs/10 mL urine respectively. Prevalence of infection in male (54.1%) and female (60.3%) individuals showed no significant variation (P>0.05). However, prevalence of infection was age dependent with those in age groups 3-5 and 12-14 years having the least and highest prevalence of infection respectively (P<0.05). Microhaematuria and proteinuria varied significantly with ages of the pupils with least (14.0, 40.0%) and highest (60.0, 80.0%) prevalence recorded in age groups 3-5 and 15-19 years respectively (P<0.05). Proteinuria showed higher sensitivity (80.3%) compared to microhaematuria (73.3%). Schistosomiasis is highly endemic in the study area and the use of microhaematuria and proteinuria for mapping the infected population prior treatment could be adopted.

Fabrication of Fresnel zone plate lens in fused silica glass using femtosecond laser lithography technology

This paper expresses maskless formation of Fresnel zone plate (FZP) lens on fused silica glass surface using femtosecond laser lithography technology. The FZP lens consists of a series of concentric rings that has been encoded on a glass surface using femtosecond laser irradiation followed by chemical etching and stripping. To compare the performance of the FZP lens with traditional laser induced FZP, we also fabricated FZP on the surface of and inside fused silica glass using femtosecond laser direct writing. In all the cases, the FZP lenses have a focal length of 50 mm. In addition, we fabricated a 25-mm focal length FZP lens by means of femtosecond laser lithography. Compared to traditional femtosecond laser direct writing, femtosecond laser lithography technique offers smooth patterning of materials. Consequently, femtosecond laser lithography engraved FZP lens yields considerably higher diffraction efficiency. Besides, we investigated the diffraction pattern of the fabricated FZP lenses. Using these FZP lenses, we are able to observe microletters encoded on an aluminum coated poly-methylmethacrylate surface indicating excellent focusing and imaging capability of the FZP lenses. The proposed maskless technology is simple compared to other lithography techniques, representing great potential for small-scale manufacturing of similar kinds of optical/photonics devices.

Investigation into the removal of an easy-care crosslinking agent from cotton and the subsequent regeneration of lyocell-type fibres

Dimethylol dihydroxyethylene urea (DMDHEU)-treated cotton fabrics were treated with alkali or alternatively acid followed by alkali for increasing time periods, and their effectiveness in removing the crosslinking agent was investigated by surface (X-ray photoelectron spectroscopy) analysis, bulk analysis, crease recovery angle performance and solubility in specific solvents. The cellulose yield after the chemical stripping processes was established and the effect of the acid and alkali treatments on the degree of polymerisation of the resultant cellulose determined. Surface and bulk analyses and solubility tests suggested that alkali alone could not remove the DMDHEU from the crease-resist-treated cotton fabric. However, a sequential acid/alkali treatment effectively removed the easy-care finish from the cotton fabric and produced a commercially viable yield of cellulose.

A Biological Approach for Color-Stripping of Cotton Fabric Dyed with C.I. Reactive Black 5 Using Fungal Enzymes from Solid State Fermentation

The problem of uneven and faulty dyeing in the finished quality of fabrics is usually tackled through a chemical stripping process to remove the loose dyes from the surface of dyed cotton fabrics. This research work was undertaken to investigate the color stripping of cotton fabric dyed with C.I. reactive black 5 in an environmentally-friendly way using enzymes instead of applying chemicals. Such bio-degradable and economical enzymes were prepared by growing white rot fungus Ganoderma lucidum IBL-05 under the optimized conditions of solid state fermentation (SSF). The biological color stripping process using SSF-enzyme extract was optimized for necessary parameters for effective color strippingsuch as SSF-enzyme concentration, pH, temperature and the duration of the enzyme reaction. The color stripping efficiency of this enzymatic reaction process was evaluated by measuring the K/S values of dyed fabric before and after the color stripping. In the present study 70.81% color stripping of dyed fabric was achieved using a cheaper preparation of crude enzyme extract consisting of three significant enzymes lignin peroxidase (EC 1.11.1.14) (530U/mL), manganese peroxidase (EC 1.11.1.13) (395U/mL) and laccase (EC 1.10.3.2) (68U/mL) under the optimized reaction conditions of stripping medium pH 4.5, at 30°Creaction temperature, and 10 days period of stripping. This biological approach is environmentally friendly as compared to chemical methods used for color stripping in textile industry. Keywords: Cotton-fabric, reactive-dye, color stripping, ganoderma lucidum IBL-05, solid-state fermentation, lignin peroxidase, manganese peroxidase, laccase.

Development of an imaging system for the detection of alumina on turbine blades

An imaging system capable of detecting alumina on turbine blades by acquiring LED-induced fluorescence images has been developed. Acquiring fluorescence images at adjacent spectral bands allows the system to distinguish alumina from fluorescent surface contaminants. Repair and overhaul processes require that alumina is entirely removed from the blades by grit blasting and chemical stripping. The capability of the system to detect alumina has been investigated with two series of turbine blades provided by Rolls-Royce plc. The results illustrate that the system provides a superior inspection method to visual assessment when ascertaining whether alumina is present on turbine blades during repair and overhaul processes.

Molecular water in nominally unhydrated carbonated hydroxylapatite: The key to a better understanding of bone mineral

Despite numerous analytical studies, the exact nature of the mineral component of bone is not yet totally defined, even though it is recognized as a type of carbonated hydroxylapatite. The present study addresses the hydration state of bone mineral through Raman spectroscopic and thermogravimetric analysis of 56 samples of carbonated apatite containing from 1 to 17 wt% CO 3 , synthesized in H 2 O or D 2 O. Focus is on the relation between the concentration of molecular water (as distinguished from hydroxyl ions) and the concentration of carbonate in the apatite. Raman spectra confirm the presence of molecular water as part of the crystalline structure in all the aqueously precipitated carbonated apatites. TGA results quantitatively document that, regardless of the concentration of carbonate in the structure, all hydroxylapatites contain ~3 wt% of structurally incorporated water in addition to multiple wt% adsorbed water. We spectroscopically confirmed that natural bone mineral also contains structurally incorporated molecular H 2 O based on independent analyses of bone by means of spectral stripping (subtracting the spectrum of collagen from that of bone) and chemical stripping (chemically removing the collagen content of bone prior to analysis). Taken together, the above data support a model in which water molecules densely populate the apatite channels regardless of the abundance of hydroxyl vacancies. We hypothesize that water molecules keep the apatite channels stable even when 80% of the hydroxyl sites are vacant (typical in bone), hinder carbonate ions from substituting for hydroxyl ions in the channels, and help regulate chemical access to the channels (e.g., ion exchange, entry of small molecules). Our results show that bone apatite is not a “flawed hydroxylapatite,” but instead a definable mineralogical entity, a combined hydrated-hydroxylated calcium phosphate phase of the form Ca 10−x [(PO 4 ) 6−x (CO 3 ) x ](OH) 2−x ·nH 2 O, where n ~ 1.5. Water is therefore not an accidental, but rather an essential, component of bone mineral and other natural and synthetic low-temperature carbonated apatite phases.

Halitosis: a review of the etiologic factors and association with systemic conditions and its management.

Halitosis is a general term defined as an unpleasant or offensive odor emanating from the breath, arising from either oral or nonoral sources. Extraoral factors, such as ear-nose-throat conditions or gastrointestinal, respiratory, and systemic diseases, may also contribute to oral malodor. Although, halitosis has a multifactorial etiology, local factors play an important role in the majority of cases. Halitosis may lead to significant personal discomfort and social embarrassment. Assessment of halitosis can be performed using organoleptic measurements, sulfide monitoring, gas chromatography, microbial testing and chemical test strips. Management approaches are based on masking oral malodor, reducing the levels of volatile organic compounds (VOCs) and volatile sulfur compounds (VSCs), and mechanical and/or chemical treatment. This review aims to identify the etiology of oral halitosis, describe the methods available for assessment and differential diagnosis and introduce a variety of management strategies. The importance of a multidisciplinary approach for the improvement of overall health and for the management and prevention of halitosis is highlighted.

Numerical Simulation of Chemical Stripping Process in Resid Fluid Catalytic Cracking Stripper

Abstract The chemical stripping process in a commercial scale V-baffled resid fluid catalytic cracking stripper was simulated using computational fluid dynamics method. At the outset, it was assumed that the stripping steam initially desorbs hydrocarbons from the catalysts, and the hydrocarbons are then cracked through thermal and catalytic cracking reactions before entering the disengager. The Eulerian–Eulerian two-fluid model coupled with a modified drag model was applied to simulate the gas–solid flow behavior. A desorption model and five-lump kinetic model for thermal and catalytic cracking were utilized to represent the desorption and cracking processes during stripping. The flow modeling results indicated that three different flow regions exist in the stripper: bubbling flow, intermediate flow and turbulent flow. Increasing gas velocity improves the flow conditions of the gas, but adversely affects the particle flow. The degree of mixing of the gas and solid increases along the flowing direction. The results of reaction modeling showed that about 80% of hydrocarbons desorbed from the catalysts. The amount of desorbed oil increases with bed height leading to an increase of heavy oil in the disengager which induces coking problem. By increasing the catalyst temperature, the partial pressure of heavy oil can be lowered down which helps to decrease the disengager coking.

A study of particulate matter concentration released during laser paint removal process on car coated substrate

Normalization mass (N) of particulate matter (PM) per one laser shot and 1.0 cm2 released during the laser irradiation were measured on three different types of car coated substrate samples A, B and C by using DustTrak Aerosol Monitor 8520. The highest N of PM1.0 and PM10.0 were 0.0485 mg/shot/cm2 and 0.0766 mg/shot/cm2 mg/shot/cm2 safe than conventional chemical stripping process in term of health implications prevention and safety managements. beam size for Sample A, 0.0890 mg/shot/cm2 and 0.0634 mg/shot/cm2 and 0.1728 mg/shot/cm2 for Sample B and 0.0530 for Sample C, respectively. Laser paint removal technique is considered

A simplified method for the evaluation of the performance of coal fired power plant with carbon capture

This paper presents a study of carbon capture systems based on chemical absorption and stripping with amines in pulverized coal fired power plants. The technical feasibility is shown for a 90% CO2 removal on 100% of the exhaust gas flow rate.A simplified method to calculate the performance penalty in comparison with the original power plant is presented including the effect of coal ultimate analysis. The method is verified with data from an existing 75 MW coal fired power plant.The economic analysis is presented in terms of cost of electricity and cost of carbon capture and the results are that the cost of electricity nearly doubles in comparison with the reference plant, whereas the cost of captured CO2 is considerably higher than the actual cost of CO2 in the carbon trading markets.

The Structure and Corrosion Process Characterization of Galvannealed and Galvanized Steel Sheets

The dissolution process of galvannealed (GA) and galvanized (GI) coating was examined by correlating a chemical stripping test in 1MNaCl+0.01MH2SO4solution. The key time of dissolution process of coating was found via measuring the variation of free corrosion potential. Through coating metallographic observations at the key point, the dissolution process of coating can be clear. There are four Fe-Zn intermetallic phases in GA coating, namely gamma-1,gamma,delta and zeta phases, from the substrate. The compressed part of GA and GI coatings was the initial of corrosion process. The net crack will be emerging on the delta phase, which width graduallyincreasing until stripping. Pitting corrosion occurred on the GI coating in the solution containing Cl-ion, the area and depth of pit gradually increasing until stripping. The corrosion potential of Fe2Al5Znxinhibition layer is about-0.8VSCE.

Hydroxyurea is associated with lower prevalence of albuminuria in adults with sickle cell disease

Albuminuria is an early manifestation of sickle cell nephropathy. Prior small case series suggests benefit of hydroxyurea in reducing albuminuria, with a similar trend noted in pediatric studies. We aimed to comprehensively evaluate hydroxyurea use and prevalence of albuminuria in adult sickle cell patients. We performed a cross-sectional study of 149 adult patients followed between 2000 and 2011 in a comprehensive sickle cell clinic. All patients were assessed for albuminuria either by direct measurement or by urinary chemical strip (dipstick) testing. Urinary albumin-to-creatinine ratios (UACRs) were available for 112 patients. Hydroxyurea exposure was defined as ≥3 months of therapy before the assessment of albuminuria. Albuminuria was defined as either UACR ≥30 mg/g or ≥1+ proteinuria on two separate dipsticks. We constructed a multivariate logistic regression model to assess the association between hydroxyurea and albuminuria. The prevalence of albuminuria was lower among patients on hydroxyurea (34.7 versus 55.4%; P = 0.01) as was median albumin excretion (17.9 versus 40.5 mg/g; P = 0.04). In multivariate analysis, hydroxyurea was associated with a lower likelihood of albuminuria (odds ratio 0.28, 95% CI: 0.11-0.75, P = 0.01), adjusting for age, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use, tricuspid regurgitant jet velocity, hypertension and acute chest syndrome. In our population of sickle cell patients, those using hydroxyurea were less than one-third as likely to exhibit albuminuria. Hydroxyurea use may prevent development of overt nephropathy or the progression of sickle cell disease nephropathy to end-stage renal disease, and its use for this indication merits further investigation.

A study into the re‐processing of pure tin termination finishes into tin‐lead

PurposeThe purpose of this paper is to present a process (chemical stripping) that can be used to remove pure tin plating from component leads and propose this activity as a mitigation strategy for tin whisker risk reduction associated with spacecraft hardware. The problems associated with the nucleation and growth of tin whiskers are stated. Present contractual requirements, having the purpose of avoiding the selection of pure tin plating, are highlighted to those not familiar with spacecraft standards.Design/methodology/approachThe key issue here is that the process must remove pure tin from the entire length of terminations present on a wide range of component types. A resilient component can be dipped into liquid solder directly to the component's body in order to remove pure tin by alloying it with tin‐lead. However, delicate heat‐sensitive devices and those with glass‐to‐metal seals can suffer from the effect of thermal shock associated with immersion of their leads/terminations into molten solder. Solder dipping was performed on chemically stripped terminations but, in the specific case of the delicate components, the solder was prevented from wetting along the complete length of the exposed base metal or barrier layer metal. Any negative effect of the chemical stripping solution was assessed by inspection of each components' markings, their construction materials and, after tin‐dipping, a wide range of standard tests were performed on re‐processed devices in order to check that they had not degraded either physically or electrically.FindingsThe majority of components that were re‐processed by chemical stripping, and subsequently solder‐dipped, suffered no degradation from either of these processes. In order to avoid the removal of identification markings it was found that the bodies of certain components should not be completely immersed into the chemical stripping solution. Devices sensitive to heat or thermal shock could be stripped and their leads partially re‐tinned by immersion into liquid solder to a predetermined depth. A short length of exposed bare termination substrate adjacent to a seal is considered, for the purpose of this study, to be acceptable.Originality/valueThe European space industry has not previously utilized chemical stripping as a viable method for removing pure tin from components and other space hardware. The complete procedure for stripping and solder‐dipping will be of benefit to companies manufacturing products for industries that have exemption from the RoHS lead‐free directives.

Precisão da tira reagente e do exame microscópico da urina no diagnóstico de infecções do trato urinário em porcas

O diagnóstico de infecção do trato urinário (ITU) em porcas geralmente é feito com o auxílio de tiras reagentes, por ser um método rápido, prático e passível de ser realizado na própria granja. O exame microscópico da urina raramente é utilizado em granjas por ser uma técnica mais demorada e trabalhosa. No entanto, não existem estudos sobre a precisão destas duas técnicas no diagnóstico de ITU nesta espécie. O objetivo deste estudo foi avaliar a precisão da tira reagente e do exame microscópico da urina no diagnóstico de ITU em porcas, comparando-os com o exame bacteriológico da urina. Para selecionar as porcas que iriam compor o estudo foi realizado um exame químico prévio com tira reagente, do qual foram selecionadas 139 porcas, 66 positivas para nitrito na tira reagente e 73 negativas. No dia seguinte foi realizada uma nova coleta de urina destas 139 porcas para realização da urinálise completa, que incluiu os exames físico, químico, microscópico e microbiológico destas amostras de urina. Os resultados demonstraram que a prova de nitrito da tira reagente apresentou 100% de especificidade e 93% de sensibilidade. A especificidade do exame microscópico para bacteriúria foi de 82% e a sensibilidade de 100%. O diagnóstico de ITU com o uso de tiras reagentes e/ou com exame microscópico da urina é confiável, quando comparado com o exame bacteriológico da urina, o que torna possível o diagnóstico rápido de ITU em porcas na granja.

Presumptive blood test using Hemastix® with EDTA in archaeology

A presumptive test is a rapid screening method that indicates the possible identity of a substance. To ensure a presumptive test is reliable, accurate and replicable, it has to be validated. In this paper we present a method validation for the cost-effective, presumptive blood test, Hemastix® with sodium ethylenediaminetetraacetic acid (EDTA) specifically for archaeology and buried residues. Hemastix®, a haemoglobin specific chemical reagent test strip (Hb-CRTS), was used with the addition of a chelating agent (EDTA) which increases the specificity of this test. It was conducted using a collection of 146 substances (plant, animal, metal compounds, chemical solutions including blood), 6 experimentally degraded samples, 177 experimental artefacts, 238 reference samples (on microscope slides) and 39 mixtures of substances. We also compared the Hemastix® and Hemastix® with EDTA test to two other Hb-CRTSs (URS-10 and Chemstrip® 10MD) and two additional presumptive tests, the tetramethylbenzidine (TMB) test and the phenolphthalein test. The results demonstrate that Hemastix® is the most specific, sensitive and cost-effective presumptive test evaluated which can be substituted with any other Hb-CRTS. Although the longevity and survival of haemoglobin on archaeological artefacts requires further investigation, the method validation described here supports Hemastix® performed with EDTA as being a reliable presumptive test for the presence of residual blood on buried artefacts.

Urogenital schistosomiasis and urological assessment of hematuria in preschool-aged children in rural communities of Nigeria

ObjectiveThe study evaluates the prevalence of urogenital schistosomiasis and diagnostic performance of chemical reagent strips used for disease diagnosis in preschool-aged children (≤5 years) in Nigeria rural communities. Patients and methodsUrine samples from 419 children were observed microscopically for Schistosoma haematobium and screened for hematuria using standard urine chemical reagent strips. ResultsPrevalence and intensity of infection were 9.8% and 14.4 eggs/10 ml of urine, respectively. Prevalence of infection was similar in girls (10%) and boys (9.6%) (p > 0.05). The intensity of infection was higher in boys (17.1 eggs/10 ml of urine) than in girls (12.8 eggs/10 ml of urine); however, this was not gender dependent (p > 0.05). The occurrence of hematuria was not associated with gender (p > 0.05), but was associated with prevalence of infection (p < 0.05). ConclusionInfection with S. haematobium occurs early in life in the communities and although intensity of infection is low, it could have serious implications in disease transmission. Hematuria, although moderately sensitive to infection, is an important morbidity indicator of urogenital schistosomiasis in the study population.

Heavy metal removal from solutions using metallic iron

Metallic iron enables an effective heavy metal removal from the single Cu(II), Cr(VI), Zn(II), Ni(II), Pb(II) and Cd(II) solutions and from their mixture under batch conditions and in the flow mode. The kinetic experiments of metal removal and analysis of precipitate formed indicated a more complicated mechanism of the decontamination process as compared to that of ordinary reduction of metal ions with metallic iron. Chemical, FTIR and X-ray analyses of the precipitate show its chemical change with time. Metal ions in solutions were determined using chemical analysis and anodic stripping voltammetry with the bismuth film electrode.

Topology of NBCe1 Protein Transmembrane Segment 1 and Structural Effect of Proximal Renal Tubular Acidosis (pRTA) S427L Mutation

In the kidney proximal tubule, NBCe1-A plays a critical role in absorbing HCO3(-) from cell to blood. NBCe1-A transmembrane segment 1 (TM1) is involved in forming part of the ion permeation pathway, and a missense mutation S427L in TM1 impairs ion transport, causing proximal renal tubular acidosis. In the present study, we examined the topology of NBCe1-A-TM1 in detail and its structural perturbation induced by S427L. We analyzed the N-terminal cytoplasmic region (Cys-389-Gln-424) of NBCe1-A-TM1 using the substituted cysteine scanning accessibility method combined with extensive chemical stripping, in situ chemical probing, and functional transport assays. NBCe1-A-TM1 was previously modeled on the anion exchanger 1 TM1 (AE1-TM1); however, our data demonstrated that the topology of AE1-TM1 differs significantly from NBCe1-A-TM1. Our findings revealed that NBCe1-A-TM1 is unusually long, consisting of 31 membrane-embedded amino acids (Phe-412 to Thr-442). The linker region (Arg-394-Pro-411) between the N terminus of TM1 and the cytoplasmic domain is minimally exposed to aqueous and is potentially folded in a helical structure that intimately interacts with the NBCe1-A cytoplasmic domain. In contrast, AE1-TM1 contains 25 amino acids connected to an aqueous-exposed cytoplasmic region. Based on our new NBCe1-A-TM1 model, Ser-427 resides in the middle of TM1. Leucine substitution at Ser-427 blocks the normal aqueous access to Thr-442, Ala-435, and Lys-404, implying a significant alteration of NBCe1-TM1 orientation. Our study provides novel structural insights into the pathogenic mechanism of S427L in mediating proximal renal tubular acidosis.

Electrochemical Resource Recovery from Digestate to Prevent Ammonia Toxicity during Anaerobic Digestion

Ammonia inhibition during anaerobic digestion limits the substrate loading rate and endangers process stability. Furthermore, digestates are interesting feedstocks for nutrient recovery. In this lab-scale study, an electrochemical cell was used to investigate the NH(4)(+) flux from anode to cathode. Under optimal conditions with synthetic wastewater, an NH(4)(+) charge transfer efficiency of 96% and NH(4)(+) flux of 120 g N m(-2) d(-1) could be obtained at a concomitant electricity input of 5 kWh kg(-1) N removed. A more selective NH(4)(+) transfer could be established by maintaining a high concentration of other cations in the cathode compartment. Comparable NH(4)(+) fluxes could be obtained with digestate at an electrical power input of 13 kWh kg(-1) N removed and 41% current efficiency. The ammonium level in the digestate could be lowered from 2.1 to 0.8 - 1.2 g N L(-1). Interestingly, also potassium fluxes of up to 241 g K(+) m(-2) d(-1) could be obtained at 23% current efficiency. As the cathode can be operated at high pH without the need for chemical addition, stripping and absorption of dissolved ammonia could reach 100% efficiency. By valorization of the generated side products, this technology shows economic potential for practical application.

Comparative Study on Chemical Stripping of Titanium Oxide Films Formed on Titanium Alloy

Abstract Two methods for stripping of anodic oxide films formed on titanium alloys Ti-6.5Al-1Mo-1V-2Zr without hydrofluoric acid or fluoride were studied: i using hydrogen peroxide with sulfuric acid and ii using hydrogen peroxide with sodium hydroxide. The morphologies and microstructures of the oxide films before and after stripping were compared by SEM and Raman spectroscopy. The surface topography and roughness of the samples were detected by AFM. The results show that the oxide films can be stripped both by the two methods and the stripping process is affected by the microstructure of the matrix material obviously. β or platelet α phases are more affected by the solution i while globular α phase is preferentially dissolved by the solution ii. The surface stripped by solution ii is flatter than that by solution i. Compared to solution i, solution ii presents better environmental friendly result and lower cost.