Man Species Research Articles

Effect of loading type in concrete deep beam with strut reinforcement

Abstract This study examined eight specimens of two groups of deep beam (DB) with the same dimensions and reinforcement quantity, where the first group had four specimens tested under two-point loads and the second group had four specimens tested under one-point load (Ammash HK, AL-Mousawi MM. Experimental investigation of deep beam reinforced with different types of reinforcement. Eng Technol Appl Sci Res. 2021;11(2):7585–90.) where both groups have the same reinforcement and the dimensions and difference between the groups was only the type of load. Digital image correlation technology software was used to verify the results. Upon examining the results, each group had one reference specimen with conventional reinforcement and the other three specimens were with strut reinforcement. It was observed that the strut reinforcement technique was more effective than the conventional reinforcement. This study also found that the load capacity was decreased at two-point loads from one-point load. The results from the present study were compared to those from a prior study (Ammash HK, AL-Mousawi MM. Experimental investigation of deep beam reinforced with different types of reinforcement. Eng Technol Appl Sci Res. 2021;11(2):7585–90.) that only employed a one-point load. The concrete type, its dimensions, and its method of reinforcing were the same as Ammash and AL-Mousawi’s (Experimental investigation of deep beam reinforced with different types of reinforcement. Eng Technol Appl Sci Res. 2021;11(2):7585–90.) study. The maximum load capacity for SC (Reference DB specimen) and S10 (the deep strut beam employed a specimen with 100% reinforcement from the reinforced web) specimens for one-point load were more tolerant to stress than the two-point loads, with 15% for SC and 27% for S10 as both specimens had comparable amounts of reinforcement. When a force is applied that is less than the sum of the two load points, cracks occur in the shear and flexural zones at one load point. We have found that the use of two-point loads leads to a decrease in the maximum load capacity of specimens when compared with a one-point load. It was also noted that cracks are formed in the shear and flexural zones at one-point load when a load less than the two-point load is applied. It was also observed that when two-point loads were applied to a specimen, the displacement was less than half of what it was when tested under a one-point load, and the strain in specimens examined under two-point load was lower than in specimens examined under one point load.

The Effect of Recasting on Microhardness of Cobalt/Chromium Base Metal Alloys

Castings made of base metals include the cobalt/chromium alloy. This alloy is frequently used in dentistry to make crowns, bridges, and partial dentures. This alloy was first promoted as a less expensive option to cast gold that had even better physical and mechanical properties and approximately comparable bioco mpatibility. It was better suited for long-span bridges and cast prostheses. Aim: to assess how recasting affects the cobalt/chromium base metal alloys' microhardness. Material and Methods: 42 disc-shaped specimens of cobalt/chrome alloy measuring 5 mm in diameter and 3 mm in thickness were prepared. The cast specimens were divi ded into three groups based on the weight of the newly and pr eviously cast Co/Cr alloy addition: the first group was 14 specimens of (new cast) alloy; the second group was 14 specimens of (50% new cast+50% old cast) alloy; and the third group was 14 specimens of (old cast) alloy. All the speci mens were subjected to measuring the microhardness prope rty by using a digital microhardness tester. Results: Using a student t-test, it was determined that there was no significant difference in the microhardness between the two gr oups (new cast) and (new cast + old cast), and that there was al so no significant difference between the groups (new cast + ol d cast) and (old cast) (P-value p>0.05), yet that there was a highly significant difference between the two groups (new cast) and (old cast) (P-value P<0.01). Conclusion: The incl usion of different ratios of fresh and recast Co/Cr alloys can affect the microhardness. Also, the recast Co/Cr metal alloy has shown excellent results for microhardness property.

The Effect of Various Disinfection Methods on The Tensile Bond Strength of Soft Lining Material

Disinfection of dentures and resilient denture liners were preferred for cross-contamination treatment and better safety. Nevertheless, it has been found that these techniques affect the physical and mechanical properties of denture liners. Objective: To evaluate the impact of various disinfection methods on the tensile bond strength of acrylic soft liner. Material and Methods: 25 samples were made, then divided randomly into five groups (4 disinfection groups as well as a control group), after the daily disinfection procedure, distilled water was used to store the samples at room temperature. After 30 days, a universal testing device (Gester, China) was used to assess the tens ile bond strength. The machine applied force to the specim ens at a crosshead constant speed of 5 mm/minute until failure was recorded. Statistics software (SPSS) was used to analyze the measurements. Results: After 30 days of regular ex posure to different disinfection methods, a greater mean value for bond strength showed in the control group while the lesse r value was in the chlorhexidine group. No significant difference was found between the control and Protefix tablet groups. The sodium hypochlorite and microwave groups had no significant difference between them, but they were significantly different from the control, Protefix tablet, and chlorhexidine groups. the chlorhexidine group was significantly different from the control and other disinfected groups. Conclusion: All disinfected soft liners revealed a decrease i n tensile bond strength, which was not significant with the protefix cleansing tablet but significant with the chlorhexidine, sodium hypochlorite, and microwave regimes.

A predictive approach for thermal fatigue crack growth behaviour of shot peened Ni75 alloy

This study presents an approach to predict the effects of shot peening on the thermal fatigue crack propagation behaviour of nickel-based Ni75 alloy. For this purpose, from an engineering perspective, comprising experimental tests data and finite element simulations, were used to estimate the thermal fatigue crack propagation behaviour of the material. Despite many other studies that have been performed to evaluate the fatigue crack growth behavior, only a few were previously conducted on thermal fatigue damage in different types of materials. Furthermore, the interaction of shot peening treatment and thermal fatigue crack propagation behavior is rare. Comparison of the results from the experimental test and FE model showed that the model appropriately predicted the thermal fatigue crack growth behaviour. The fracture mechanism evaluation showed that the compressive residual stress, induced by shot peening treatment, reduced both the crack opening and secondary crack branching. Also, the results show the crack initiation life of the shot peened specimen (SP) is about 2.5 times more than the non shotpeened specimen (NSP). Moreover, the microscopy analysis showed that the failure mechanism of the NSP and SP specimens were transgranular and a combination of intergranular and transgranular cracking, respectively

The influence of the CIELAB parameters on the perception of color after the use of whitening toothpastes

Aim: To evaluate the influence of the parameters L* a* b* on the variation of the color of bovine tooth enamel submitted to artificial darkening, after simulated brushing, with whitening toothpastes containing blue covarine. Methods: To undertake this study in vitro, 60 specimens (SP) were divided into 6 groups (n=10): control group (CGwater) and 5 test groups (GT1-Colgate Total 12, GT2-Oral-B 3D White Perfection, GT3- Colgate Luminous Instant White, GT4-CloseUp White Diamond Attraction, GT5-Sorriso Xtreme White). The specimens were darkened with coffee and submitted to simulated brushing for 6, 12, and 24 months. The alteration in the color was evaluated using CIELAB parameters and the ΔL, Δa, Δb and ΔE were calculated. The data was analyzed through generalized linear models using the R program and considering a level of significance of 5%. Results: The parameters L*, a* and the ΔL, Δa obtained better results in the test group than in the control group. There were no statistical differences between CG and the test groups for the evaluation of the b* parameter. In the evaluation of the Δb, the GT3 differed statistically from the CG. In relation to the ΔE, all the group tests showed a variation in color statistically greater than that of the CG and the GT4 showed the greatest variation, not differing from the GT3 during the periods studied. Conclusion: The mechanical and optical whitening agents positively influenced the values L*a* and b*, as well as in its variations and in the ΔE. It is important to emphasize, however, that to analyze tooth whitening it is necessary to evaluate their parameters together.

Effect of Vertical End-Milling Operations up on some Mechanical Properties of Free Machining Brass Plates.(Dept.M)

Test sp ecimens made of as-received free machining brass plates having dimensions of (10x180x100) x 10-3m were vertical end milled from one or from two sides in some cases. Milling conditions varied from (0.1 to 1.2) x 10-3m depth of cut, and feed speed ranging between (0.4 to 1.58) x10-3 m/s for spindle speeds of (2.67 to 13.30) rev./s. Flat tensile test sp ecimens were made out of the same milled plates having 10x10-3m thickness and 50x10-3m gauge length. It was found, for cases of one side milling, that the increase of depth of cut from 0.1x10-3 m to 1.2x10-3m led to increases in the values of the maximum true tensilestrength from (600 to 650) MPa. On the other hand, the corresponding values. for double sides milling cases,varied from (620 to 670) MPa. The corresponding fracture strains ranged from 0.16 to 0.20 for cases ofmilling from one side to 0.125 to 0.175 for double sides milling cases. In all cases, slight decreases in the material true ultimate tensile stresses with noticeable increases in the fracture strains were noted upon the increase in spindle sp eeds. No change in the material strain-hardening exponents were noted through all the conducted tests. Material fatigue strength was taken to be equal to 0.3 of the true ultimate strength.

Energy release rate of a single edge cracked specimen subjected to large deformation

The single edge notch specimen (SEN) is commonly used to measure the fracture toughness, or critical energy release rate of soft elastic materials. To measure toughness, an expression for the energy release rate, J, the mechanical energy available for growing the crack per unit area, is needed. Since strains in these fracture experiments can easily exceed several hundred percent, large deformation analysis is needed to calculate J. An approximate formula for J in SEN samples subjected to moderately large deformation was given by Rivlin and Thomas in J Polym Sci 10:291–318. https://doi.org/10.1002/pol.1953.120100303 (1953) and Greensmith in J Appl Polymer Sci 7:993–1002. https://doi.org/10.1002/app.1963.070070316 (1963). However, this formula works only for small crack lengths, for stretch ratio up to two and does not match the linear elastic result in the limit of small strains. In this paper we carry out a series of finite element (FE) simulations to obtain accurate approximations that are valid for all practical crack lengths and strain levels. Our FE result shows that the small crack approximation of by Rivlin and Thomas in J Polym Sci 10:291–318. https://doi.org/10.1002/pol.1953.120100303 (1953) does not work well in the small strain regime, and in particular, result of Greensmith in J Appl Polymer Sci 7:993–1002. https://doi.org/10.1002/app.1963.070070316 (1963) underestimates the energy release rate for stretch ratios less than 1.5.

A study of the mechanical properties and appearance of efflorescence in paving bricks under different curing environments

Taiwan has witnessed rapid economic development in recent years, and with urban development, the planning and design of compressed paving units and pervious ground tile structures are focused on the demand for esthetic appearance in addition to practical functioning and legal requirements for strength and water permeability. In this study, the efflorescence appearance of structures was effectively reduced using calcium carbonate crystallization from the water purification and softening process to fill the pores in generic high-pressure bricks. The same water-to-binder ratio of 0.35 was used for three different mix proportions, and 20 cm × 20 cm × 6 cm general high-pressure bricks, calcium carbonate high-pressure bricks, and pervious bricks were made under a 50 kg/cm2 molding pressure at a concrete-brick-making plant. The samples were cured in five different environments with curing times of 2, 7, 28, 56 and 91 days. The effect of the curing age, the curing environment and the brick type on the hardness, solidity and appearance of efflorescence of the bricks were analyzed in terms of the compressive strength, the ultrasonic pulse velocity, and the coefficient of permeability, using Paint.net image analysis, scraping rate tests, SEM analysis and EDS analysis.The test results showed that the compressive strengths of the general high-pressure bricks, the calcium carbonate high-pressure bricks and the pervious bricks were 46.78 MPa–84.97 MPa, 56.89 MPa–100.23 MPa and 35.38 MPa–59.20 MPa, respectively. The ultrasonic pulse velocities were 3296 m/s–4524 m/s, 3567 m/s–5703 m/s and 2623 m/s–4319 m/s, respectively. The coefficient of permeability of the pervious bricks was larger than 1 × 10–2 cm/sec. Quantitative analysis of efflorescence using Painet.net image analysis and scraping rate tests showed that the ratio of the efflorescence to the total area at the surface or bottom of the bricks and the scraping rate were larger for curing on hardened concrete than under other curing conditions. The efflorescence that was generated on the bottom layer of the bricks was higher than that on the surface layer by 5.31%–19.82%. Microscopic analysis of the specimens (SEM) showed the existence of many crystalloid Ca (OH)2 colloids that accounted for 20–25% of the cement volume. EDS analysis showed that Ca was the main element in efflorescence, at 6.64%, which was much higher than the percentage of other elements. To summarize the results, curing in a cling film seal can inhibit efflorescence crystallization.

INFLUENCE OF FATIGUE ON BENDING OF Pinus caribaea WOOD

ABSTRACT This research aimed to evaluate the effect of the number of fatigue cycles (NC, 0 – reference, 450, 4500, 45000, and 90000) for frequencies (Fr) of oscillation equal to 0.5 and 1.0 Hz on the modulus of elasticity (Em) and operating stress (σm) in the static bending of Pinus caribaea wood. Em and σm were determined taking into account three specimens (SPEC) manufactured for reference condition and another three for each of the four NC levels and each Fr level, resulting in 27 SPEC. Sixty experimental determinations were obtained, being the approximate total time of sample exposure to fatigue of 350 hours. The same specimens used to determine Em and σm for the reference condition were also used (via non-destructive tests) to obtain these properties for all fatigue cycles. The frequency and number of cycles significantly influenced both investigated properties. Reductions in Em and σm values were observed after 45000 cycles. The progressive increase in the number of fatigue cycles caused more marked reductions in mechanical properties when compared to the increase in the frequency of oscillation.

Human avian influenza virus serotypes in a tertiary hospital in Nigeria

Background: Nigeria suffered waves of Highly Pathog enic Avian Influenza (HPAI) outbreaks that peaked twice in February 2006 and February 2007. The outbr eaks affected 3,057 commercial and rural household farms causing 1.3 million of the country’ s poultry destroyed. The burden of Influenza is likely to be under estimated and because of the uns table nature of the virus it call for the mapping o f this virus to specific region, this study therefore seeks to identify the types, prevalence, strain, predilection of the organism so as to monitor the o ccurrence of influenza in this part of the country with the aim of providing a base line level of intervent ion of influenza virus and find the candidate virus for vaccine selection and production. This study is a c ross sectional survey, our target populations were all pediatric and adult patients admitted at the pe diatrics and internal medicine department of ATBUTH who has met the criteria for presence of cough, fev er (>37 o C), nasal congestion and dyspnoea. Samples were collected and analyzed using the polym erase chain reaction (PCR), for the presence and sub typing of influenza viruses in respiratory spec imens. Overall 5% of the samples collected tested positive for human influenza type A and B. During a verage epidemics, overall attack rates are estimate d to be 10–20%, but in certain susceptible population s such as schoolchildren or nursing home residents, attack rates of 40–50% may occur. 60% of the positi ve results were among the female samples where as 40% from the male samples

Speciation and precipitation of heavy metals in high-metal and high-acid mine waters from the Iberian Pyrite Belt (Portugal).

Acid mine waters (AMW) collected during high- and low-flow water conditions from the Lousal, Aljustrel, and São Domingos mining areas (Iberian Pyrite Belt) were physicochemically analyzed. Speciation calculation using PHREEQC code confirms the predominance of Men+ and Me-SO4 species in AMW samples. Higher concentration of sulfate species (Me-SO4) than free ion species (Men+, i.e., Al, Fe, and Pb) were found, whereas opposite behavior is verified for Mg, Cu, and Zn. A high mobility of Zn than Cu and Pb was identified. The sulfate species distribution shows that Fe3+-SO42-, SO42-, HSO4-, Al-SO4, MgSO40, and CaSO40 are the dominant species, in agreement with the simple and mixed metal sulfates and oxy-hydroxysulphates precipitated from AMW. The saturation indices (SI) of melanterite and epsomite show a positive correlation with Cu and Zn concentrations in AMW, which are frequently retained in simple metal sulfates. Lead is well correlated with jarosite and alunite (at least in very acid conditions) than with simple metal sulfates. The Pb for K substitution in jarosite occurs as increasing Pb concentration in solution. Lead mobility is also controlled by anglesite precipitation (a fairly insoluble sulfate), where a positive correlation was ascertained when the SI approaches equilibrium. The zeta potential of AMW decreased as pH increased due to colloidal particles aggregation, where water species change from SO42- to OH- species during acid to alkaline conditions, respectively. The AMW samples were supersaturated in schwertmannite and goethite, confirmed by the Men+-SO4, Men+-Fe-O-OH, or Men+-S-O-Fe-O complexes identified by attenuated total reflectance infrared spectroscopy (ATR-IR). The ATR-IR spectrum of an AMW sample with pH 3.5 (sample L1) shows well-defined vibration plans attributed to SO4 tetrahedron bonded with Fe-(oxy)hydroxides and the Men+ sorbed by either SO4 or Fe-(oxy)hydroxides. For samples with lower pH values (pH~2.5-samples SD1 and SD4), the vibration plans attributed to Men+ sorption are not evidenced, indicating its release in solution. The sorption of heavy metals on the first precipitated simple metal sulfates was ascertained by scanning electron microscopy coupled with X-ray spectrometry (SEM-EDX), where X-ray maps of Cu and Zn confirm a distribution of both metals in the melanterite structure.

접착제에서 발생하는 휘발성유기화합물(VOCs)에 대한 안정성 연구

ABSTRACT In this study, the stability of the adhesive was de termined through the Oddy Test that is Verification Test for potential damage by various materials. And to find the f actor causing the corrosion of the metal samples, the adhesives and coatings those are usually used in the metal preservation process were selected and treat ed on the samples. Six kinds of adhesives and four kinds of metal sp ecimens Fe, Pb, Cu, Ag were used. As results, the weight change showed high increasement in the rate of weight ch ange 29.87% of Fe sample. The chromatic ity measurement showed the high change value of the Cellulose-based adhesive. In case of the VOCs test from adhesive by using GC-MS, Acetic acid was detected from all six kinds of the adhesives. Compared to cellulose-bas ed adhesives and the other adhesives, the amount of VOCs per 1mg concentration is higher than 900 times and was det ected small amount of Formic acid. This is assumed to be facilitated by acid impurities and the light. This reaction was considered as the result of reducing a large amount of molecular and of generating a large amount of Nox. And thus the reacted sulfur changes wa s considered as the factor for causing corrosion.

가력하중을 통한 CST30제진댐퍼시스템의 구조성능 평가

The performance enhancement of various structural building syst ems from natural hazards has become an inctreasingly important issue in engineering field. In this paper, visco-elas tic(VE) CST30 damping systems were tested under cyclic loadings to evaluate their performance in terms of ductility an d energy dissipation. Main test variables are relative shear stiffness, rate of loading frequency, and thickness of specimens to evaluate the seismic capacity based on the performance criteria. This experiment was performed using a total of 12 spe cimens, subjected to cyclic loadings up to a shear deformation of 500%. All the CST30 dampers provided a ductile a nd stable hysterestic behavior when subjected to the demands of large shear stiffness and different loading frequenc ies. The test results showed that the CST30 dampers are an effective damping systems to enhance the buildings performance for remodeling and retrofit of buildings.

A New Species ofFelicola(Phthiraptera: Ischnocera: Trichodectidae) from the Forest Giant Pouched Rat (Cricetomys emini) in Cameroon, Africa and a Redescription ofFelicola hopkinsiBedford, 1936

Of the 56 described species in the genus Felicola, 55 are parasites of carnivores and 1 has been described from a primate (Perez and Palma, 2001). To date, no representative of this genus has been reported from a rodent. Such high host specificity is not uncommon among chewing lice, especially the trichodectids. As pointed out by Hopkins (1949), “each species of Trichodectidae occurs normally as a rule, on only one species of host, but occasionally on several hosts which, though very closely related, are not conspecific.” In the present study, 1 of 15 Forest Giant Pouched Rats (Cricetomys emini Wrough ton 1910) from Bawa, West Province, Cameroon (approx. 5o20'N, 9o 54'E), purchased as food items by the first author during May 2007, was infested with 10 chewing lice, 6 females (5 adults and 1 juvenile) and 4 males (2 adults and 2 juveniles). This region constitutes a montane tropical forest lying along a volcanic ridge in western Cameroon. Tchuinkam et al. (2010) described the ge og raphy and climate of the region. Exceedingly little information is available on the ectoparasitic fauna of C. emini. Cook and Richardson (2010) reported on epifaunistic earwigs associated with these individual rats. No other ectoparasites were observed on the rat infested with chewing lice. Lice were collected with watchmaker’s forceps and fixed in 70% ethanol. Soft tissues were dissolved with a 20% aqueous solution of potassium hydroxide. Speci mens were stained with acid fuchsin, cleared in clove oil, and mounted in Canada balsam as described by Palma (1978). Preliminary study revealed the lice to represent a previously undescribed species in the genus Felicola. Comparison to descriptions of all previously described species of Felicola (Price, 2003) re vealed the new species to be most morphologically similar to Felicola hopkinsi Bedford, 1936. The original description of F. hopkinsi was based on 2 individuals, a male and female collected from an African Palm Civet (Nandinia binotata arborea) in Kampala, Uganda in 1933. Although Bedford (1936) did not reference deposition of type specimens in his original description of F. hopkinsi, specimens designated in writing on the original slide labels as the male holotype and

Nonlinear Finite Element Modeling of Red Meranti Compression at an Angle to the Grain

In an orthotropic material on its mechanical properties. The aim of this research numerical simulation using the compression strength of angle to the grain rang ing analysis were obtained from clear spe the numerical results, various cross grain specimen s were tested under uniaxial compressive stress. It has been shown in this study that distortion energy of an compressive strength at proportional limit for cros s grain specimens. Compa rison with the experimental results show 12° and 80° the FEA predict experimental results. Compared to compressive strength at a value, ranging from 13.2% to 30.5 incorporating Hill's yield compressive strength at an angle to the grain. orthotropic material , the grain angle has a significant influence mechanical properties. The aim of this research was to perform a numerical simulation using a nonlinear finite element analysis (FEA) to obtain strength of the Red Meranti ( shorea spp. ) timber species at an ing from 12° to 80°. The material properties needed fo r the obtained from clear spe cimen tests. To investigate the validity of the numerical results, various cross grain specimen s were tested under uniaxial It has been shown in this study that an FEA based on the an orthotropic material can be used to obtain the compressive strength at proportional limit for cros s grain specimens. Compa - experimental results show ed that for a cross grain angle between predict ed the strength to be 9.4% to 33.6% lower than the Compared to using Hankinson's formula to predict the compressive strength at a cross grain angle, using the FEA always gave a low er ranging from 13.2% to 30.5 %. Based on these results, an FEA yield criterion is a conservative method for predicting compressive strength at an angle to the grain. ; FEA ; grain angle; Hill's yield criterion; red meranti.

First data on sperm heteromorphism in the mussels Crenomytilus grayanus and Mytilus trossulus (Bivalvia) from the Sea of Japan

Bivalve mollusks of the family Mytilidae inhabit almost all regions of the world ocean. Representatives of the genera Mytilus and Crenomytilus that are impor� tant objects of the mariculture and commercial catch� ing, dominate in coastal waters of the Sea of Japan. In the study of reproductive strategies of mytilids, their spermatozoa were described by a number of authors [3, 8, 12–14]. The data covered, mainly, peculiarities of morphology and ultrastructure of spermatozoa and traditionally were used for decision of questions in tax� onomy of this group of mollusks. Transmission elec� tron microscopy has shown that mytilids are charac� terized by a “primitive” type of the spermatozoon, which is usually found in invertebrate animals with external fertilization [10]. Until recent time, it has been considered that only one sperm type is inherent in each species of mytilids. However, we have revealed unusual cases of the heteromorphism in the sperm of Gray’s mussel Crenomytilus grayanus (Dunker, 1853) and the Pacific blue mussel Mytilus trossulus Gould, 1850. The goal of this study was detailed analysis of the heteromorphism phenomenon in male gametes of these two species. Mature gonads of mollusks, collected in the Vostok Bay (the Sea of Japan) in July–August 2011 were used for the study. Material was collected at the Vostok Marine Biological Station of the Institute of Marine Biology. Under laboratory conditions, gonads were removed and crashed into small pieces, which were fixed at 4°C in 2.5% glutaraldehyde in 0.2 M cacody� late buffer solution (pH 7.4) for 2–4 h. Then, the spec� imens were washed in 0.1 M cacodylate buffer solution for 15–20 min. The sperm suspension was placed by a pipette onto the surface of Thermanox cover slips (Cat. no. 72280), incubated until they sedimented (for 30 min), and then dehydrated in a series of accelerat� ing concentrations of ethanol, gradually bringing to a pure acetone. After that, the specimens were critical�

NONLINEAR FE MODELLING OF ANCHORAGE BOND IN REINFORCED CONCRETE

The transfer of forces from the surrounding concret e to the reinforcing bars in reinforced concrete (R C) can be influenced by several parameters. In this paper an attempt has been made to study the influence of specimen geometry, bar di ameter, strength of concrete, lateral confinement and embedment length on the bon d properties of concrete. The embedment length of t he bar was varied between 50mm and 400mm by varying the diameter of the bar, strength of concrete and lateral confinement. The d ifferent bar diameters of 16, 20 and 25mm were selected along with three differen t concrete strengths of 25, 40 and 65MPa. The speci mens with the above parameters were modeled by using a nonlinear finite element analysis package. It has been found that fthe same geometry, the specimens with small bond length exhibited high bon d strength. With the range of bar diameters conside red the bond strength of concrete decreases as the diameter of the bar incre ases. The splitting failure has been observed in un confined concrete, while the pullout failure was predominant when the concrete l aterally confined. In case of large embedment lengt h, the post peak plateau is prolonged with small diameter bars when compared to the large diameter bars. The descending branch of the bond stress-slip response with large diameter bars has been found to be steep.

EFFECT OF COLD ROLLING ON LOW CYCLE FATIGUE BEHAVIOR OF A NEAR -ALPHA TITANIUM ALLOY

Four cold reductions, viz. 2.5, 5, 7.5 and 10 perce nt are given to a near- α Titanium alloy Timetal 834, following solution tre atment in α+β range and stabilization. LCF tests were conducted at room temperature in total strain control mode at Δe t/2 from ± 0.45% to ± 1.05%. Prior to LCF testing, gage section of the sp ecimens was elecrtopolished to reveal the surface m odifications, resulting from fatigue testing. It was observed that cold rolling considerably enhanced fatigue life of the alloy.

The fabrication and characterization of Al/SiC-MMC castings produced by vacuum assisted solidmould investment casting process

In this paper, a promising manufacturing approach to cast metal matrix composites is proposed. In order to produce metal matrix composites by investment casting, SiC preforms were fabricated in 3D structure. Afterwards, A6063 aluminium alloy matrix material was infiltrated into preforms which were placed in the solid investment casting moulds with vacuum assistance. Preforms were characterized using Archimedes' test, scanning electron microscope anâ Xray diffraction analysis. Also, fabricated cast speci� mens, were characterized using hardness tests, image analysis and scanning electron microscope observa� tions. The results show that, in the vacuum assisted solidmould investment casting method; infiltration, of the preforms by molten metal was successfully achieved. Moreover, hardness of the composite higher than the matrix up to ratio of 100% by SiC reinforcement and T6 heat treatment.

First Report ofCampyloneura virgula(Hemiptera: Miridae: Bryocorinae) in Connecticut

The Old World dicyphine plant bug Campyloneura virgula (Herrich-Schaef fer) is known from most European countries, Algeria, Asia Minor and Turk estan (Kerzhner and Josifov, 1999). It was first reported as occurring in west ern North America (British Columbia) in 1949 (Downes, 1957). Collection records from Brit ish Columbia (1946, 1950), Oregon (1957-1979, 1982), Cali fornia (1964, 1969), and western Washington (1975-1979, 2008) were published by Lattin and Stonedahl (1984) and Henry (2012). Recently, the species has been documented in the eastern United States in Maryland (from 2007-2011), and Virginia (2011); in addition, a specimen was identified from Yonkers, New York, from a collection made in 1995. These recent records suggest that C. virgula is well-estab lished in the eastern United States (Henry, 2012). Campyloneura virgula is a predator of aphids, mites, psocids, psyllids, and other small arthropods, and is known to bite humans. It has been found on a large variety of plants (Aceraceae, Anacardiaceae, Betulaceae, Ericaceae, Fab aceae, Fagaceae, Lauraceae, Oleaceae, Rhamnaceae, Rosaceae, Salicaceae, Tiliaceae, Ul maceae and Urticaceae). The species is known to overwinter as eggs in Eng land and as adults in Europe (Henry, 2012). In June 2012, Campyloneura virgula was collected for the first time in Con nec ticut (New Haven Co., North Haven). Six specimens were found on the leaves of a 70-year-old copper beech tree (Fagus sylvatica purpurea), a species upon which the mirid had not been reported previously in North America, although it had been collected on F. sylvatica in Europe (Downes, 1957). One speci men was observed feeding on honeydew, a behavior previously noted (Wheel er, 2001). Previous collections of this species in North America were made from June to August. All specimens collected in Connecticut were female. This is consistent with most past collections, and the species is known to be parth enogenetic (Carayon, 1989; Henry, 2012). The specimens were all collected by the author: 25 June 2012 – 1 female; 27 June 2012 – 1 female; 29 June 2012 – 4 females (one feeding on honeydew). The specimens from 27 June (1) and 29 June (3) have been deposited in the Yale Peabody Museum of Natural History, Division of Entomology. Given its small size (length 3.80-4.20 mm) (Henry, 2012), this insect is not readily collected by hand (as was done for the current report), and recognition of species presence generally requires purposeful collection by beating or sweeping 76 ENTOMOLOGICAL NEWS