Perforated Region Research Articles

English

Conical and hemispherical nose-shaped cylindrical impactors have been used in drop weightimpact experiments on 3.1 mm CSM-polyester laminated plates. Based on experimental results,various failure mechanisms and energy absorbed in different failure modes are identified and calculated.It is found that the damage area beyond a certain value of impact energy does not increase. Theperforation geometry is the same as that of the impactor irrespective of increased crack length, andcomplete rotation of petals takes place at impactors radius. It is also observed that the crack lengthincreases with decrease in contact area. But, when the nose is sharp (5 mm hemispherical nose), thereis no extended crack beyond perforated region. Blunt nosed (truncated conical impactor with 10 mmnose dia) impactors cause more number of petals/cracks than 10 mm hemispherical nosed impactorand less than 5 mm hemispherical nosed impactor. The petals formed by a cylindrical impactor with40 mm hemispherical nose are unequal in size, whereas in the case of conical impactors, these areequal. At lower energies, blunt nosed impactors cause more delamination than the hemisphericalones, and at higher energy, it is the reverse. It is found that there exist many visible concentriccircular ring hinge mechanisms at the top surface of plates.

Prevention of infective endocarditis: Guidelines from the American Heart Association: A guideline from the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group

The purpose of this statement is to update the recommendations by the American Heart Association (AHA) for the prevention of infective endocarditis, which were last published in 1997. and A writing group appointed by the AHA for their expertise in prevention and treatment of infective endocarditis (IE) with liaison members representing the American Dental Association, the Infectious Diseases Society of America and the American Academy of Pediatrics. The writing group reviewed input from national and international experts on IE. The recommendations in this document reflect analyses of relevant literature regarding procedure-related bacteremia and IE; in vitro susceptibility data of the most common microorganisms, which cause IE; results of prophylactic studies in animal models of experimental endocarditis; and retrospective and prospective studies of prevention of IE. MEDLINE database searches from 1950 through 2006 were done for English language articles using the following search terms: endocarditis, infective endocarditis, prophylaxis, prevention, antibiotic, antimicrobial, pathogens, organisms, dental, gastrointestinal, genitourinary, streptococcus, enterococcus, staphylococcus, respiratory, dental surgery, pathogenesis, vaccine, immunization and bacteremia. The reference lists of the identified articles were also searched. The writing group also searched the AHA online library. The American College of Cardiology/AHA classification of recommendations and levels of evidence for practice guidelines were used. The article subsequently was reviewed by outside experts not affiliated with the writing group and by the AHA Science Advisory and Coordinating Committee. The major changes in the updated recommendations include the following. (1) The committee concluded that only an extremely small number of cases of IE might be prevented by antibiotic prophylaxis for dental procedures even if such prophylactic therapy were 100 percent effective. (2) IE prophylaxis for dental procedures should be recommended only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from IE. (3) For patients with these underlying cardiac conditions, prophylaxis is recommended for all dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. (4) Prophylaxis is not recommended based solely on an increased lifetime risk of acquisition of IE. (5) Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a genitourinary or gastrointestinal tract procedure. These changes are intended to define more clearly when IE prophylaxis is or is not recommended and to provide more uniform and consistent global recommendations.

Electromagnetic band‐gap (EBG) structures using combined inductive and capacitive elements and chirping‐and‐tapering technique

Purpose – To perform studies and comparisons on the electromagnetic band‐gap (EBG) structures, which are constructed by using a combination of inductive and capacitive elements printed on guided‐wave transmission lines, and by applying a chirping‐and‐tapering technique.Design/methodology/approach – An in‐house solver based on finite‐difference time‐domain (FDTD) method is adopted for analysis. Conventionally, EBG characteristics are formed by a series of perforations, considered as capacitive elements, on the ground plane(s). To enhance the performance, an additional inductive element is implemented, which is realized by narrowing the strip over the respective perforated regions. For further enhancement, a chirping‐and‐tapering technique is applied on the combined EBG structures for comparisons.Findings – Through scattering parameter analysis, it was found that the EBG structures using combined inductive and capacitive elements exhibit a band‐gap behavior superior to the ones built with only inductive or ...

Prevention of Infective Endocarditis

Background— The purpose of this statement is to update the recommendations by the American Heart Association (AHA) for the prevention of infective endocarditis that were last published in 1997. Methods and Results— A writing group was appointed by the AHA for their expertise in prevention and treatment of infective endocarditis, with liaison members representing the American Dental Association, the Infectious Diseases Society of America, and the American Academy of Pediatrics. The writing group reviewed input from national and international experts on infective endocarditis. The recommendations in this document reflect analyses of relevant literature regarding procedure-related bacteremia and infective endocarditis, in vitro susceptibility data of the most common microorganisms that cause infective endocarditis, results of prophylactic studies in animal models of experimental endocarditis, and retrospective and prospective studies of prevention of infective endocarditis. MEDLINE database searches from 1950 to 2006 were done for English-language papers using the following search terms: endocarditis, infective endocarditis, prophylaxis, prevention, antibiotic, antimicrobial, pathogens, organisms, dental, gastrointestinal, genitourinary, streptococcus, enterococcus, staphylococcus, respiratory, dental surgery, pathogenesis, vaccine, immunization, and bacteremia. The reference lists of the identified papers were also searched. We also searched the AHA online library. The American College of Cardiology/AHA classification of recommendations and levels of evidence for practice guidelines were used. The paper was subsequently reviewed by outside experts not affiliated with the writing group and by the AHA Science Advisory and Coordinating Committee. Conclusions— The major changes in the updated recommendations include the following: (1) The Committee concluded that only an extremely small number of cases of infective endocarditis might be prevented by antibiotic prophylaxis for dental procedures even if such prophylactic therapy were 100% effective. (2) Infective endocarditis prophylaxis for dental procedures is reasonable only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis. (3) For patients with these underlying cardiac conditions, prophylaxis is reasonable for all dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. (4) Prophylaxis is not recommended based solely on an increased lifetime risk of acquisition of infective endocarditis. (5) Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a genitourinary or gastrointestinal tract procedure. These changes are intended to define more clearly when infective endocarditis prophylaxis is or is not recommended and to provide more uniform and consistent global recommendations.

Prevention of infective endocarditis: Guidelines from the American Heart Association: A guideline from the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group

<h2>ABSTRACT </h2><h3>Background</h3> The purpose of this statement is to update the recommendations by the American Heart Association (AHA) for the prevention of infective endocarditis, which were last published in 1997. <h3>Methods and Results</h3> A writing group appointed by the AHA for their expertise in prevention and treatment of infective endocarditis (IE) with liaison members representing the American Dental Association, the Infectious Diseases Society of America and the American Academy of Pediatrics. The writing group reviewed input from national and international experts on IE. The recommendations in this document reflect analyses of relevant literature regarding procedure-related bacteremia and IE; in vitro susceptibility data of the most common microorganisms, which cause IE; results of prophylactic studies in animal models of experimental endocarditis; and retrospective and prospective studies of prevention of IE. MEDLINE database searches from 1950 through 2006 were done for English language articles using the following search terms: endocarditis, infective endocarditis, prophylaxis, prevention, antibiotic, antimicrobial, pathogens, organisms, dental, gastrointestinal, genitourinary, streptococcus, enterococcus, staphylococcus, respiratory, dental surgery, pathogenesis, vaccine, immunization and bacteremia. The reference lists of the identified articles were also searched. The writing group also searched the AHA online library. The American College of Cardiology/AHA classification of recommendations and levels of evidence for practice guidelines were used. The article subsequently was reviewed by outside experts not affiliated with the writing group and by the AHA Science Advisory and Coordinating Committee. <h3>Conclusions</h3> The major changes in the updated recommendations include the following. (1) The committee concluded that only an extremely small number of cases of IE might be prevented by antibiotic prophylaxis for dental procedures even if such prophylactic therapy were 100 percent effective. (2) IE prophylaxis for dental procedures should be recommended only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from IE. (3) For patients with these underlying cardiac conditions, prophylaxis is recommended for all dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. (4) Prophylaxis is not recommended based solely on an increased lifetime risk of acquisition of IE. (5) Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a genitourinary or gastrointestinal tract procedure. These changes are intended to define more clearly when IE prophylaxis is or is not recommended and to provide more uniform and consistent global recommendations.

Gas-Condensate Flow in Perforated Regions

Summary The most crucial region with regard to affecting well productivity is the perforated region. Considerable effort has been directed to study this subject mathematically by many investigators, but they have been mainly focused on single-phase flow, while two-phase flow has received less attention. It has been demonstrated, first by Danesh et al. (1994) and subsequently by other researchers (Henderson et al. 1995; Blom et al. 1997; Ali et al. 1997), that the gas and condensate relative permeability (kr) can increase significantly by increasing the flow rate, contrary to the common understanding. This effect, known as positive coupling, complicates the flow of gas and condensate near the wellbore even further when it competes with the inertial forces at higher velocities typical of those around perforation tips. The flow of gas and condensate in the perforated region was studied in this work using a finite-element modeling approach. The model allows for changes in fluid properties and accounts for the positive coupling and negative inertial effects using a fractional-flow-based relative-permeability correlation. A sensitivity analysis on the impact of perforation characteristics such as density, phasing, length, and radius as well as that of fluid properties, rock characteristics, wellbore radius, fractional flow, and rate on well productivity was conducted, resulting in some valuable practical guidelines for optimum perforation design. Introduction The effect of perforation characteristics on the well flow efficiency has been studied by many investigators. Muskat presented the first analytical treatment of the problem (1943). In his analysis, perforations were represented by mathematical sinks distributed spirally around the wellbore but did not extend into the formation. Other early investigators used the finite-difference modeling technique to examine the productivity aspects of perforated completions (Harris 1966; Hong 1975). However, because of the limitations of the finite-difference method, these studies considered mostly unrealistic perforation geometries to avoid mathematical complexities. Later investigators applied the finite-element method, which models the geometry of the perforation with greater precision (Locke 1981; Tariq 1987). Tariq (1987) presented results of finite-element modeling of single-phase steady-state flow in perforated completions with and without the non-Darcy (inertial) effect for a linear core and a full 3D system. Although his results for single-phase flow are widely used, there are reports on lack of required accuracy at large perforation lengths and in the non-Darcy cases (Behie and Settari 1993; Jamiolahmady et al. 2006a).

Application of Ultrasonography for Blunt Laryngo-Cervical-Tracheal Injury: Moriwaki Y, Sugiyama M, Fujita S, et al. J Trauma 2006;61:1156–61

This study from Japan utilized ultrasound (US) for the preliminary evaluation of blunt laryngo-cervical-tracheal injury (BLCTI) using a fabricated model of the laryngo-tracheal anatomy in addition to four patients with suspected BLCTI. Given the varied uses of ultrasound in emergency medicine, especially in trauma situations, the authors wished to explore the possibility of determining BLCTI using US. Their hypothesis was initially tested using a closed cylindrical hollow model, representing the laryngeal-tracheal anatomy, with a protruding mass placed in either the anterior, anterolateral, or lateral regions of the inner lumen signifying the region of perforation where mucous and blood clots collect.

遊離耳介軟骨移植による鼻中隔穿孔閉鎖術の経験

Nasal septum perforation occurs via many causes such as during surgery head trauma or through systemic disease.Crusting or hemorrhage occurs from the perforated region, and a lot of cases decrease the quality of life of patients remarkably.In addition, a perforation choke operation is chosen for cases whereby control is poor only by conservative treatment such as a topical treatment or chemical administration as therapy. As for the perforation choke operation, various operation methods have been reported. Perforation cause, size, and perforation ambient histionic property vary among cases leading to difficulty in the choice of operation methods.We report one example of nasal septum perforation that we were able to close by isolation via auricular cartilage transplant.The case was a 64 year old woman. The chief complaint was recurrent epistaxis. We completely closed the nasal septum perforation by isolation auricular cartilage transplant and achieved symptomatic improvement.As we were able to close the perforation good cartilaginous survival with the perichondrium was suggested.

A study of the weak shock wave propagating over a porous wall/cavity system

The present computational study addresses the attenuation of the shock wave propagating in a duct, using a porous wall/cavity system. In the present study, a weak shock wave propagating over the porous wall/cavity system is investigated with computational fluid dynamics. A total variation diminishing scheme is employed to solve the unsteady, two-dimensional, compressible, Navier-Stokes equations. The Mach number of an initial shock wave is changed in the range from 1.02 to 1.12. Several different types of porous wall/cavity systems are tested to investigate the passive control effects. The results show that wall pressure strongly fluctuates due to diffraction and reflection processes of the shock waves behind the incident shock wave. From the results, it is understood that for effective alleviation of tunnel impulse waves, the length of the perforated region should be sufficiently long.

Benchmark of Plate Forming and Weld Distortion Process

A circular flat plate with a perforated central region is to be formed by dies into a dome and then welded onto a cylindrical shell. After welding, the dome must be spherical within a narrow tolerance band. This plate forming and welding is simulated using large deflection theory elastic-plastic finite element analysis. The manufacturing assessment is performed so that the dies may be designed to compensate for plate distortions that occur during various stages of manufacturing, including the effects of weld distortion. The manufacturing simulation benchmarks against measurements taken at several manufacturing stages from existing hardware. The manufacturing simulation process can then be used for future applications of similar geometries.

衝撃力を受ける気球皮膜の貫通挙動

A new composite fabric has been developed for a balloon envelope possessing both excellent strength and gas barrier as well as low density, and perforation behavior under impact load is presently focused. The perforation test was experimentally conducted to clarify the effect of loading rate on the fracture behavior, together with the tensile test to evaluate the strain rate effect on the strength of the present material. Rate dependence of the stress strain relation of the material was clearly identified; the strength is significantly increased while the strain at fracture is decreased with a rise of strain rate. This fact well explains the experimental results where perforation strength is almost independent of loading rate, but the behavior is much more brittle due to localized deformation around perforated region at impact loading. It is also found that delamination of inter-laminar fibers in the composite fabric is able to relieve stress concentration and will be served to prevent a brittle fracturing independent of loading rate.

Effects of cortical bone perforation on experimental guided bone regeneration

This study was designed to evaluate the effects of cortical bone perforation histologically and histomorphometrically on guided bone regeneration (GBR) in rabbits. After elimination of the periosteum, cortical bone defects of two sizes were made in the external cortical plate of the frontal bone (Group A: 1 x 15 mm; Group B: 3 x 15 mm). A non-resorbable membrane filled with autogenous blood was placed in the experimental area and secured with titanium pins. After 1 and 2 weeks, vascularized connective tissue and new bone were generated in the space surrounding the defects in both the groups. The amount of vascularized connective tissue generated in Group B was greater than that in Group A at 1 week. Alkaline phosphatase (ALP) was expressed on the bone surrounding the perforation. The expression of ALP was more extensive in Group B than in Group A and was proportional to the breadth of perforation. At 2 weeks, the perforated region was almost covered with new bone in Group A. ALP was expressed at the periphery of newly formed bone. The expression of ALP was proportional to the breadth and height of perforation. At 6 weeks, semicircular outgrowth of bone towards the periphery of the perforated region was observed in both the groups. Newly formed bone volume and ALP expression in Group B were more extensive than those in Group A. At 12 weeks, the space was filled with bone and connective tissue in both the groups. There was no difference in ALP expression between Groups A and B. Histomorphometric analysis showed significant differences between both the groups (two-way ANOVA, P<0.01). We conclude that a larger perforation is associated with prompter bone formation in the secluded space during GBR.

Ballistic penetration response of high strength bainitic steel

An experimental program has been undertaken to study the phenomen of both normal impact of 7.62 mm AP bullets against tested plates, and of ballistic penetration response of high strength bainitic steel. A large amount of general plastic flow changes the texture of plate material in the traveling direction of the projectile. Number cracks are connected to the white-etched shear bands, in the vicinity of the perforated region. The hardening of ultra fme grained microstructure within the adiabatic shear bands greatly overrides the prior quenching effect. At the boundary, elongated grain structure is extended in a direction of shear bands. Microhardness measurements of pressure weld of projectile and crater bottom material revealed of thermal softening and strain hardening effects respectively.

Analysis of a Tubesheet Undergoing Rapid Transient Thermal Loading

Some Class I CANDU heat exchanger tubesheets experience very high in-plane thermal gradients under Level A/B transients. If the thermal stresses exceed the ratcheting limit of the ASME Boiler and Pressure Vessel Code, shakedown has to be demonstrated by an elastic-plastic analysis. The choice of the plasticity model and its parameters must ensure that shakedown is predicted only if it occurs in reality. Differences to uniaxial modeling are discussed, and a conservative way of predicting shakedown is presented. The perforated region of the tubesheet is replaced by an equivalent solid plate with anisotropic yield properties (Hill’s yield criterion). A lower-bound shakedown limit for this material is derived. An example analysis is presented that has been performed using a commercial finite element code. [S0094-9930(00)00303-6]

Yield Criteria for the Elastic-Plastic Design of Tubesheets With Triangular Penetration Pattern

To perform an elastic-plastic finite element analysis of a tubesheet, the anisotropic stiffness and yield properties of the perforated region are represented by an equivalent solid plate. Traditional anisotropic yield criteria (like Hill’s criterion) do not give accurate predictions under general biaxial loading because they neglect the plastic compressibility of the perforated material. A compressible-anisotropic second-order yield criterion is derived which can model both the actual out-of-plane and in-plane behavior. Using an equivalent stress vector, the in-plane symmetry properties of the second-order compressible model are examined for a triangular penetration pattern. Generally, the tubesheet symmetry is not precisely reflected by this model. Additional planes of symmetry can be introduced with a higher-order yield function. A fourth-order yield function with the required symmetry properties is presented which is in excellent agreement with the response of a finite element, elastic-plastic model of a tubesheet ligament under in-plane biaxial loading.

PERFORATION OF THE TRANSVERSE COLON DUE TO CYTOMEGALOVIRUS ENTERITIS IN A PATIENT WITH WERNER'S SYNDROME

A 49-year-old woman with Werner's syndrome was admitted to the hospital because of epigastralgia. Her abdomen was distended with muscular defence. Abdominal CT scan demonstrated the presence of free air. She was diagnosed as having panperitonitis due to perforation of the gastrointestinal (GI) tract, and an emergency operation was performed. At surgery, amounts of stool in the abdominal cavity was found and a perforated region of the transverse colon was recognized. A partial resection of the transverse colon with a colostomy was performed. Microscopic examination showed ulcer formation with infiltration of lots of lymphocytes with acidophilic intranuclear inclusion bodies. On immunohistochemical staining, these inclusion bodies were positive to anti-CMV antibody. There have been no reports of the case with Werner's syndrome and idiopathic colonic perforation due to CMV infection. Opportunitic CMV infection should be included in the defferential diagnosis of perforation of the GI tract of unknown cause in an immuno-compromised host.

Application of Equivalent Elastic Methods in Three-Dimensional Finite Element Structural Analysis

This paper describes use of equivalent solid (EQS) modeling to obtain efficient solutions to perforated material problems using three-dimensional finite element analysis (3-D-FEA) programs. It is shown that EQS modeling in 3-D-FEA requires an EQS constitutive relationship with a sufficient number of independent constants to allow the EQS material to respond according to the elastic symmetry of the penetration pattern. It is also shown that a 3-D-FEA submodel approach to calculate peak stresses and ligament stresses from EQS results is very accurate and preferred over more traditional stress multiplier approaches. The method is demonstrated on the problem of a transversely pressurized simply supported plate with a central divider lane separating two perforated regions with circular penetrations arranged in a square pattern. A 3-D-FEA solution for a model that incorporates each penetration explicitly is used for comparison with results from an EQS solution for the plate. Results for deflection and stresses from the EQS solution are within 3 percent of results from the explicit 3-D-FE model. A solution to the sample problem is also provided using the procedures in the ASME B&amp;PV Code. The ASME B&amp;PV Code formulas for plate deflection were shown to overestimate the stiffening effects of the divider lane and the outer stiffening ring.

Observation of adiabatic shear bands formed by ballistic impact in aluminum-lithium alloys

The 2090 alloy and the Weldalite alloy with high strengths contained very few adiabatic shear bands even near the perforated region, whereas adiabatic shear bands were more easily formed in the 7039 alloy. In the front side of the impacted area, many thin delaminated sheets and a large amount of fragmentation were observed in the 2090 alloy and the Weldalite alloy, respectively. Microscopic observations of the adiabatic shear band were consistent with the fact that ballistic performance tends to increase with increasing yield strength. Particularly in the Weldalite alloy whose strength and fracture toughness were the highest of the three alloys, very few adiabatic shear bands were formed and their width was very narrow, indicating its excellent ballistic performance. For the 2090 alloy which contained heavily elongated grains and coarse grain boundary particles, many cracks formed near the perforated region and propagated along grain boundaries. These intergranular cracks possibly gave the beneficial effect on ballistic performance since they might prevent the formation of adiabatic shear bands.

772-3 Heparin Delivery at the Site of Angioplasty with a Novel Drug Delivery Sleeve: Initial Clinical Series

The LocalMed InfusaSleeve (IS) is a multi-lumen array with distal micro perforations designed to deliver agent at the site of angioplasty. Prior to the procedure, the IS is loaded onto a standard dilatation catheter (DC). Using standard technique, angioplasty is performed with the IS retracted. After lesion dilatation, the IS is tracked over the DC, aligning the micro perforation region of the IS with the balloon. The balloon is reinflated bringing the array into close proximity to the arterial wall. Agent(s) is delivered at specific pressures independent of balloon inflation. We have previously shown that agent delivery into the wall is dependent upon balloon inflation and drug delivery pressures. A pilot series was performed to evaluate the safety of heparin delivery via the IS. A total of 21 patients [emergent/urgent (2), elective cases (19)] with lesions at a variety of anatomic sites [LAD(10), LCx(3), ramus intermedius(1), RCA(6) and vein graft (1)] and complexity [ACC/AHA Lesion Type: A(8), B1(l0), B2(3)] were attempted. Following PTCA, heparin (1,000 U/ml) was delivered via the IS into the arterial lumen (balloon inflation pressure = 0.5 atm, drug delivery pressure = 40 psi). Failure to track the IS was noted in 2 cases. In 2 cases (RCA) a dissection was noted following agent infusion [NHLBI Type: A(1), B(1)]. The IS was used in conjunction with standard guide catheters [8 fr (15), 9 fr (6)], DC and guide wires. At discharge, no complications were noted. 1) The IS can be used safely at a variety of anatomic sites, 2) The IS is compatible with standard PTCA equipment. 3) Local delivery of agent via LocalMed InfusaSleeve is a promising approach to reduce abrupt closure and restenosis.

Microstructural Study of Adiabatic Shear Formed by Ballistic Impact in an HY-100 Band Steel

This article presents a study of the microstructural development of the adiabatic shear band in an HY-100 steel. The steel was deformed at a high strain rate by ballistic impact, and subsequent metallographic observations along with electron microscopy were performed. A number of white- etched shear bands were found near the perforated region, and three typical microstructural features of the adiabatic shear band were observed: elongated grain structure at the boundary between the shear band and matrix, fine equiaxed grain structure with high dislocation densities in the middle of the shear band, and relatively coarse-grained structure located between the above two structures. These microstructures might be formed in an extremely short time by the combined effects of the large temperature rise and the highly localized deformation. Since very complex phenomena might occur within the shear band, possible mechanisms, such as dynamic recovery and strain-induced dynamic phase transformation, are suggested to explain the micro- structural development of the adiabatic shear band.