Research on Fe-based impregnated diamond drill bits strengthened by Nano-NbC and Nano-WC

In order to improve the matrix performance of impregnated diamond drill bit to better meet the drilling needs,the effects of the addition of nano-WC and nano-NbC particles on the matrix material together with the mechanical properties and microstructure of the diamond-matrix composite material of the Fe-based diamond drill bit were studied by using the method of uniform formula design,regression analysis and solution finding.An indoor drilling test was also carried out using the fabricated impregnated diamond drill bit.The results showed that after the addition of nano-NbC and nano-WC,the hardness and flexural strength of the matrix material got improved,as the flexural strength of the diamond composite material increased to 4.29%,the wear-resistance ratio increased to 8.75%,and the tighter the chemical bonding between the diamond and the matrix.This,indicates that the addition of nanoparticles has a positive significance in improving the performance of the diamond composite.The results of the drilling test showed that the mechanical drilling speed of the impregnated diamond drill bit after nanoparticle strengthening is 25.85%higher than that of the conventional drill bit,and the matrix wear was increased by 17.5%.It proves that nanoparticles can improve the drilling performance and efficiency of drill bit.

Scale and Associated Factors of Using Pyrethroid-Impregnated Mosquito Nets as Fishing Tools on Nokoué Lake within Sô-Ava Municipality in Benin, 2020

Background: In lacustrine communities, whether in Benin or elsewhere, populations use impregnated mosquito nets (IMNs) as fishing nets. This depletes the lake of its fishery resources, which in turn are contaminated by the pyrethroids impregnated in the nets. This study aims to determine the scale and factors associated with the use of pyrethroid-impregnated mosquito nets as fishing tools in the municipality of Sô-Ava in Benin. Methods: This is a cross-sectional and analytical study with two components. First, a quantitative component was made up of 280 volunteers who were interviewed in the seven districts of the city. Data collection was done in two phases: the first from September to October 2020, and the second in August 2022. Data were analyzed with Stata and logistic regression was used. Another qualitative component was made up of forty participants chosen by reasoned choice, of which 32 were split into four focus groups of eight members each, and the rest participated in semi-structured interviews. Triangulation of the different sources was used to analyze the data. Results: Around 67% of the population reported using impregnated mosquito nets as fishing tools and 33% exclusively for malaria. Seasonal fishermen (ORa = 2.03, CI = 1.35 - 4.97, P = 0.004) and years of professional experience (ORa = 1.53, CI = 1.00 - 2.05, P = 0.021) increase the risk of using these nets as fishing tools. The use of insecticide-treated mosquito nets against mosquitoes causes skin scratching and impairs breathing because of the impregnation products, as reported by respondents. Conclusion: A high prevalence of inappropriate use of impregnated mosquito nets in fishing practices is highlighted in this study. Interviews in the field revealed that nets are diverted for fishing purposes to increase the volume of catches. Consequently, it will be appropriate to assess the pyrethroid content in water and fishery products.

Discussion of reasonable drilling parameters in impregnated diamond bit drilling

The impregnated diamond(ID)bit drilling is one of the main rotary drilling methods in hard rock drilling and it is widely used in mineral exploration,oil and gas exploration,mining,and construction industries.In this study,the quadratic polynomial model in ID bit drilling process was proposed as a function of controllable mechanical operating parameters,such as weight on bit(WOB)and revolutions per minute(RPM).Also,artificial neural networks(ANN)model for predicting the rate of penetration(ROP)was developed using datasets acquired during the drilling operation.The relationships among mechanical operating parameters(WOB and RPM)and ROP in ID bit drilling were analyzed using estimated quadratic polynomial model and trained ANN model.The results show that ROP has an exponential relationship with WOB,whereas ROP has linear relationship with RPM.Finally,the optimal regime of mechanical drilling parameters to achieve high ROP was confirmed using proposed model in combination with rock breaking principal.

Dry Friction and Wear Characteristics of Impregnated Graphite in a Corrosive Environment

Tribological properties of impregnated graphite are greatly influenced by preparation technology and working conditions and it’s highly susceptible to corrosion environmental impacts,but the experimental research about it are few.In this paper,three kinds of impregnated graphite samples are prepared with different degree of graphitization,the tribological properties of these samples in the dry friction environment and in a corrosive environment are analyzed and contrasted.The tribo-test results show that the friction coefficient of samples is reduced and the amount of wear of samples increase when the graphitization degree of samples increases in dry friction condition.While in a corrosive environment（samples are soaked N2O4）,the friction coefficient and amount of wear are changed little if the graphitization degree of samples are low.If the degree of graphitization increase,the friction coefficient and amount of wear of samples increase too,the amount of wear is 2 to 3 times as the samples tested in the non-corrosive environment under pv value of 30MPa？m/s.The impregnated graphite,which friction coefficient is stable and graphitization degree is in mid level,such#2,is more appropriate to have a work in the corrosion conditions.In this paper,preparation and tribological properties especially in corrosive environment of the impregnated graphite is studied,the research conclusion can provide an experimental and theoretical basis for the selection and process improvement of graphite materials,and also provide some important design parameters for contact seal works in a corrosive environment.

Extraction of cerium(Ⅳ) using tributyl phosphate impregnated resin from nitric acid medium

Tributyl phosphate （TBP） solvent was used for impregnation into Amberlite XAD-16 nonionic polymeric resin beads using the wet method to prepare solvent impregnated resin （SIR）. Undiluted TBP in a ratio to the resin support （volume to mass） of 6.0 at room temperature （RT） in 24 h was impregnated the resin with a mass ratio of 1.944, while the prepared gross sample of SIR at the ratio of solvent to resin of 3.0 was impregnated with a mass ratio of 1.88. Cerium（Ⅳ） oxide concentrate, prepared from crude Egyptian monazite sand, containing 37% cerium, 1.6% thorium and about 40% the other trivalent rare earth oxides, was used to prepare cerium（Ⅳ） nitrate solution for extraction using the prepared SIR. The impregnated resin was satisfactory for Ce（Ⅳ） extraction from nitric acid medium at room temperature. Cerium loading capacity of the impregnated resin reached 95.6% of the calculated theoretical capacity （173 g/kg （Ce/SIR）） under the conditions of 51.57 g/L cerium and 2.48 g/L thorium, 5.0 mol/L free nitric acid, solution to resin ratio of 10.0 and contacting the phases for 5.0 min. The loading capacity reached 98.75% when cerium concentration was increased to 91.43 g/L under the same conditions.

Adsorption-extraction mechanism of heavy rare earth by Cyanex272-P507 impregnated resin

Instrument of IR spectrometer and methods of saturation, equimolar series change and slope were applied to study the extraction mechanism of Cyanex272-P507 impregnated resin for heavy rare earths from hydrochloric acid solution. The results show that the molar ratio of Cyanex272-P507 to rare earth in the extraction complex is 3. Chlorine ions do not participate in coordination. The extraction reaction can be expressed as RE3＋（a） ＋ 3-HA（r） ＋ 3/2HL（r）= [REA3/2L3/2]（r） ＋ 3H＋（a） （where HA represents 2 2 Cyanex272 and HL represents P507）. The synergic extractant formed in extraction chromatography is in a form ofmonopolymer and with a chemical structure of REA3/2L3/2.

Preparation, Characterization and Luminescent Properties of MCM-41 Type Materials Impregnated with Rare Earth Complex

Hybrid materials incorporating Eu-(TTA)(3). 2H(2)O (7hereafter designated as Eu-TTA, with TTA: thenoyltrifluoroacetone) in unmodified or modified MCM-41 by 3-aminopropyl-triethoxysilane (APTES) were prepared by impregnation method. The obtained materials were characterized using X-ray diffraction (XRD), IR and diffuse reflectance spectroscopy and luminescence spectra. All the hybrid samples exhibited the characteristic emission bands of EU3+ under UV light excitation at room temperature, and the excitation spectra showed significant blue-shifts compared to the pure rare-earth complex. Although the red emission intensity in the modified hybrid was almost the half of the red emission intensity in the pure Eu-TTA complex at room temperature, the hybrid showed a much higher thermal stability due to the shielding character of the MCM-41 host.

Antimicrobial-impregnated catheters for the prevention of catheter-related bloodstream infections

Central venous catheters are commonly used in critically ill patients. Such catheterization may entail mechanica and infectious complications. The interest in catheterrelated infection lies in the morbidity, mortality and costs that it involved. Numerous contributions have been made in the prevention of catheter-related infection and the current review focuses on the possible current role of antimicrobial impregnated catheters to reduce catheter-related bloodstream infections(CRBSI). There is evidence that the use of chlorhexidine-silver sulfadiazine(CHSS), rifampicin-minocycline, or rifampicin-miconazol impregnated catheters reduce the incidence of CRBSI and costs. In addition, there are some clinical circumstances associated with higher risk of CRBSI, such as the venous catheter access and the presence of tracheostomy. Current guidelines for the prevention of CRBSI recommended the use of a CHSS or rifampicin-minocycline impregnated catheter in patients whose catheter is expected to remain in place > 5 d and if the CRBSI rate has not decreased after implementation of a comprehensive strategy to reduce it.

Impregnated Paper-Based Decorative Laminates Prepared from Lignin-Substituted Phenolic Resins

High Pressure Laminates(HPL)panels consist of stacks of self-gluing paper sheets soaked with phenol-formaldehyde(PF)resins.An important requirement for such PFs is that they must rapidly penetrate and saturate the paper pores.Partially substituting phenol with bio-based phenolic chemicals like lignin changes the physico-chemical properties of the resin and affects its ability to penetrate the paper.In this study,PF formulations containing different proportions of lignosulfonate and kraft lignin were used to prepare paper-based laminates.The penetration of a Kraft paper sheet was characterized by a recently introduced,new device measuring the conductivity between both sides of the paper sheet after a drop of resin was placed on the surface and allowed to penetrate the sheet.The main target value measured was the time required for a specific resin to completely penetrate the defined paper sample(“penetration time”).This penetration time generally depends on the molecular weight distribution,the flow behavior and the polarity of the resin which in turn are dependent on the manufacturing conditions of the resin.In the present study,the influences of the three process factors:(1)type of lignin material used for substitution,(2)lignin modification by phenolation and(3)degree of phenol substitution on the penetration times of various lignin-phenolic hybrid impregnation resins were studied using a complete twolevel three-factorial experimental design.Thin laminates made with the resins diluted in methanol were mechanically tested in terms of tensile and flexural strains,and their cross-sections were studied by light microscopy.

Scandia doped tungsten matrix for impregnated cathode

As a matrix for Sc-type impregnated cathode,scandia doped tungsten with a uniform distribution of Sc2O3 was obtained by powder metallurgy combined with the liquid-solid doping method.The microstructure and composition of the powder and the anti-ion bombardment behavior of scandium in the matrix were studied by means of SEM,EDS,XRD,and in-situ AES methods.Tungsten powder covered with scandium oxide,an ideal scandium oxide-doped tungsten powder for the preparation of Sc-type impregnated cathode,was obtained using the liquid-solid doping method.Compared with the matrix prepared with the mechanically mixed powder of tungsten and scandium oxide,Sc2O3-W matrix prepared with this kind of powder had smaller grain size and uniform distribution of scandium.Sc on the surface of Sc2O3 doped tungsten matrix had good high temperature stability and good anti-ion bombardment capability.

Adsorption of 2-naphthalenesulfonic acid/sulfuric acid/sulfurous acid from aqueous solution by iron-impregnated weakly basic resin：Equilibrium and model

Commercial grade weakly basic resin D301 was impregnated with iron through a simple method using ferric chloride. Experiments for single, bisolute and trinary competitive adsorption were carried out to investigate the adsorption behavior of 2-naphthalenesulfonic acid(NSA), sulfuric acid and sulfurous acid from their solution at 298 K onto the novel hybrid iron impregnated D301(Fe-D301). Adsorption affinity of NSA on Fe-D301 was found to be much higher than that of sulfuric acid, while adsorption affinity of sulfuric acid was slightly higher than that of sulfurous acid. The data of single-solute adsorption were fitted to the Langmuir model and the Freundlich adsorption model. The non-ideal competitive adsorbed model coupled with the single-solute adsorption models were used to predict the bisolute and trinary-solute competitive adsorption equilibria. The NICM coupled with the Langmuir model yields the favorable representation of the bisolute and trinary-solute competitive adsorption behavior.

Study of the efficacy of a Wheaton coated bottle with permethrin and deltamethrin in laboratory conditions and a WHO impregnated paper with bendiocarb in field conditions

Objective:To determine the efficacy of WHO impregnated paper and CDC coated bottle based on number of storage days and number of limes of consecutive use,in the assessment of insecticide vector susceptibility tests in laboratory and field conditions.Methods:Larvae and pupae of Anopheles gambiae s.l.mosquitoes were collected from the breeding sites in Seme-Kpodji and Cotonou districts in Southern Benin in April 2013 during the first rainy season.Anopheles gambiae s.l.mosquitoes were also collected from the breeding sites in Parakou district in Northern Benin in May 2013 at the beginning of the rainy season.Susceptibility tests were done using impregnated paper with bendiocarb(0.1%)following WHO protocol and stock solutions of permethrin(21.5 ug per bottle)and deltamethrin(12.5 ug per bottle)following CDC protocol on unfed female mosquitoes aged 2-5 days old.These bioassays were repeated a certain number of times.The temperature and relative humidity were monitored and recorded during the susceptibility tests.Results:This study showed that a WHO impregnated paper with bendiocarb could be used four times during four consecutive days in field conditions.Regarding a Wheaton coated bottle with permethrin or deltamethrin,they could be used at least three limes during four consecutive days in laboratory conditions.Conclusions:The day storage and the number of times that a WHO impregnated paper and a CDC coated bottle maintained their efficacy are useful in the assessment of insecticide vectors susceptibility tests.

ANALYSIS OF THE REMOVAL OF H_2S WITH IMPREGNATED ACTIVATED CARBON

A general mathematical model with its governing equations in dimensionless forms has beendeveloped to describe the removal of hydrogen sulfide with impregnated activated carbon.Anapproximate relationship between the sulfur capacity and the reaction time in a single carbon pellet isobtained,and criterion to ascertain the rate controlling step of the process can then be deduced.Inthe meantime,the choice of the appropriate oxygen concentration and the principle to be followedare also described.

The Principle of the Drilling by Impregnated Diamond Bits and the Classification of Rocks

Recently impregnated diamond bits have been widely applied in drilling hard and medium - hard formations in the world . It is quite necessary to study the fracturing mecha-nism of the impregnated diamond bit and the classification of rocks , which can realize optimum drilling . Using multi - parameter rotary test stand can monitor and print nine parameters . The diamond size and concentration for experiment are various and there are nearly 200 types of samples , numbering over 1000 pieces . The results of laboratory are the same as those in the field . Besides , this paper expresses that the diamond concentration of impregnated diamond bits effect the bonding strength of diamond imbedded in ma-trix . During drilling by impregnated diamond bits three ways are used to cool the bits . The contact area between impregnated diamond layer and flow , and the drilling flow through annulus carrying away heat with conduction form can be shown by equations . It is impossible to classify the rock drillability only by using single factor . The best method is to use main factors to analyse the drillability of rocks. Only in this way , the results can be applied to practice .

Separation of Tb^(3+) , Dy^(3+) , Ho^(3+) , Er^( 3+) with Solvent Impregnated Resins Containing Di-(2,4,4-trimethylpentyl) Phosphinic Acid

Solvent impregnated resins (SIR) with di (2,4,4 trimethylpentyl)phosphinic acid (Cyanex 571) were studied by adsorption of the extractant into Amberlite XAD 4; XAD 7; XAD 1180 polymeric adsorbents. The results shas that Cyanex 571/XAD 7 impregnated resins containing extractant of 0 35～0 45 g·g -1 resin have a favorable extractive activity in HCl medium. The rare earths (Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ ) are separated by using SIR as the column stationary phase. The better separation effect is obtained at lower load and slower elution rate.

Quality evaluation and control of impregnated dia-mond bit

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Preparation of Magnesia Insulation Materials by Walnut Shell Powder Impregnated with Silica Sol

In order to reduce the thermal energy loss of high temperature kilns and furnaces and lower the surface temperature of the kiln body,magnesia insulation materials were prepared using self-made magnesia porous aggregates(using high purity magnesia powder as starting material and potassium oleate as the foaming agent),middle grade magnesia powder,calcium aluminate cement,and SiO_(2) micropowder as starting materials,introducing walnut shell powder impregnated with silica sol(short for Sws)as a pore-forming agent.The effects of the Sws addition(0,10%,15%,and 20%,by mass)and the sintering temperature(1300,1350,1400,and 1480℃)on the properties of magnesia insulation materials were studied.The results show that(1)for the specimens fired at 1480℃,when the Sws addition is 10%,the cold compressive strength is 22 MPa;when the Sws addition is 20%,the thermal conductivity is 0.368 W·m^(-1)·K^(-1)(350℃);(2)nano-silica in the silica sol reacts with MgO in the matrix to form forsterite,which encapsulates the pores volatilized from the walnut shell powder and forms closed pores.

Knowledge &Utilization of Long Lasting Impregnated Nets among Housewives in Al Moneera City and Al Koozi Villages, Hodieda Governorate, Republic of Yemen 2007

Malaria is considered as one of the main health problem in the Republic of Yemen. In February 2006 National Malaria Control Program started freely distribution of Long Lasting Impregnated Nets (LLINs) for vulnerable groups to malaria infection (pregnant women and children under 5 years). After one year of distribution, there is a need to measure the use rate among vulnerable groups and explore factors affecting their use. The aim of the study was to investigate the use rate of long lasting impregnated nets among children under five years and pregnant women in Al Moneera city and Al Koozi villages of Hodieda governorate. Methodology: Cross section study with multistage sample, Random selection of one urban and one rural locality. 768 housewives were interviewed, proportionally allocated sample according to the number of vulnerable groups in each locality. Systematic random sample to select households. Results: The use rate of LLINs for vulnerable groups was 74.3% CI (71.2 - 77.4). There was no statistically significant association between the use of LLINs and residence, also with ages of housewives, occupation, type of house, but there is strong statistically significant association between use of LLINs and having correct information about how to use and to take care of them P value < 0.001, also with educational status of housewives;P value 0.03 and educational status of fathers;P value 0.01. (84%) have correct information about how to use and take care of LLINs and the main source of information was health workers who distributed them. Only 13.4% realized pregnant women as a vulnerable group to malaria infection while about 77.9% realized children as a vulnerable group to malaria infection. The main reason of LLINs use (84.8%) was protection from nuisance of insects. Conclusion and recommendations: There is shortage in the information about the protective effect of LLINs from malaria infection and the main reason of using them is protection from nuisance of insects. There is a need to increase health awareness about the role of LLINs in malaria prevention.

Recovery of Heavy Metal Using Solvent Impregnated Resin (SIR) Coupled with Donnan Dialysis

A membrane process for metal recovery from aqueous solutions was studied. Metal ions diffused from the feed compartment to the stripping compartment through an hybrid Donnan dialysis which consists to combine two ion exchange membranes with solvent impregnated resin (SIR). The aim of this work is to study the recovery of Pb(II), Ag(I) and Cu(II) from nitrate solutions by using SIR combined with classical Donnan dialysis. The resin has been prepared by impregnating the Amberlite XAD-4 using three different extractants namely: di-2-ethyl hexyl phosphine acide (D2EHPA), tris-octyl phosphine oxide (TOPO) and Diphenylthiourea (DPT). Experiments were performed as a function of nature of the extractant impregnated on the XAD-4 resin as well as the concentration in the resin phase, the stripping pH, the concentration ratio of metal ions in the feed compartment and the nature of the counter ions in strip compartment. The results show that the D2EHPA is the better extractant for the metal ions used in this work, and it’s shown a good selectivity for the separation between ions.

Characterization of molten 2LiF–BeF_2 salt impregnated into graphite matrix of fuel elements for thorium molten salt reactor

The impregnation behavior of molten 2LiF–BeF_2(FLiBe) salt into a graphite matrix of fuel elements for a solid fuel thorium molten salt reactor(TMSR-SF) at pressures varying from 0.4 to 1.0 MPa was studied by mercury intrusion, molten salt impregnation, X-ray diffraction, and scanning electron microscopy techniques.It was found that the entrance pore diameter of the graphite matrix is less than 1.0 μm and the contact angle is about 135°. The threshold impregnation pressure was found to be around 0.6 MPa experimentally, consistent with the predicted value of 0.57 MPa by the Washburn equation. With the increase of pressure from 0.6 to 1.0 MPa, the average weight gain of the matrix increased from 3.05 to 10.48%,corresponding to an impregnation volume increase from 2.74 to 9.40%. The diffraction patterns of FLiBe are found in matrices with high impregnation pressures(0.8 MPa and1.0 MPa). The FLiBe with sizes varying from tens of nanometers to a micrometer mainly occupies the open pores in the graphite matrix. The graphite matrix could inhibit the impregnation of the molten salt in the TMSR-SF with a maximum operation pressure of less than 0.5 MPa.