Special Casting Research Articles

Transient dystonic toe‐walking: differentiation from cerebral palsy and a rare explanation for some unexplained cases of idiopathic toe‐walking

We report on seven children (five males, two females) who presented with marked, often asymmetrical, toe-walking from onset of independent walking, associated with abnormal foot postures and increased tone at the ankles with characteristics of dystonia. Most of the children had presented with unusual pre-walking locomotion and a mild delay in independent walking. They did not fit into the usual categories of 'habitual' toe-walking or congenital short tendo calcaneus but nor did they have the clinical signs of spastic diplegia or of a peripheral neuromuscular disease. Normalization occurred progressively in the second to fourth years of life. The children were re-examined several years later (1 to 11y) and were normal. We believe that their persistent toe-walking corresponded to a variant of 'transient focal dystonia of infancy'. Knowledge of its existence may justify a period of observation without special investigations, surgery, or casting.

Superconductivity and Thermal Property of MgB<SUB>2</SUB>/Aluminum Matrix Composite Materials Fabricated by 3-Dimensional Penetration Casting Method

Superconductive MgB2/Al composite material with low and high volume fractions of particles were fabricated by our special pre-packing technique and 3-dimensional penetration casting method. The composite material showed homogeneous distribution of MgB2 particles in the Al-matrix with neither any aggregation of particles nor defects such as cracks or cavities. The critical temperature of superconducting transition (TC) was determined by electrical resistivity and magnetization to be about 37–39 K. Specific heat measurements further supported these TC findings. The Meissner effect was also verified in the liquid He, in which a piece of the composite floated above a permanent magnet. The thermal conductivity of the MgB2/Al composite material was about 25 W/K·m at 30 K, a value much higher than those found for NbTi or Nb3Sn superconducting wires normally used in practice, which are 0.5 and 0.2 W/K·m at 10 K, respectively. A billet of the superconducting material was successfully hot-extruded, forming a rod. The same as the billet sample, the rod showed an onset TC of electrical resistivity of 39 K.

Caste evolution and ecology: a special worker for novel prey

Individual specialization underpins the division of labour within ant societies, but only in a small minority do morphological specialists, or physical castes, exist in the workforce. The genetic conditions that allow such castes to evolve are well understood, but the ecological pressures that select for them are not. We provide compelling evidence that the task of transporting novel prey selected for an exaggerated transport caste, or 'submajor', in the army ant Eciton burchellii. This species is the only Eciton that preys upon large arthropods as well as ants, the ancestral prey type, and by comparing load-transport among Eciton species and within E. burchellii, we show that this mixed diet significantly constrains transport efficiency. Crucially, however, we also show that E. burchellii submajors are highly specialized on transporting non-ant prey, and we demonstrate experientially that it is specifically this prey type that constrains prey-transport efficiency. Our study also suggests that phylogenetic constraints associated with the Eciton lifestyle intensified selection for the exaggerated submajor of E. burchellii. Thus, we propose that a novel task may only select for a special caste when phylogenetic constraints preclude the evolution of alternative solutions. This identifies a new and potentially general scenario for the evolution of physical castes.

The influence on the distribution of interfacial stresses of embedded inclusions and voids in the adherends of bimaterial structures

In this paper, the digital photoelastic technique and finite element method (FEM) were combined to investigate the influence of embedded inclusions and voids on the distribution of interfacial stresses of bimaterial structures. A special casting procedure was employed to manufacture the bimaterial structures with and without voids and inclusions in the adherends. As indicated from the results of this paper, after introducing inclusions or voids in the adherends, the interfacial peeling stresses may become most critical.

Formation and mechanical properties of Zr-Cu-Al bulk glassy alloys

Abstract We used highly purified elements (i.e. low-oxygen-content Zr metal) and a special arc melting and casting furnace to prepare Zr 50 Cu 40 Al 10 rod-shaped bulk glassy alloy over 10 mm in diameter. In the Zr-Cu-Al alloy system, we examined the glass-forming ability in the bulk glassy state by Δ T x , T g / T l , and the Hruby factor. The Hruby factor is appropriate for evaluating glass-forming ability in the cast Zr-Cu-Al bulk glassy alloy. In order to enhance the mechanical properties even in pre-oxidized Zr-Cu-Al (oxygen concentration 1000 ppm) bulk glassy alloy, we examined the effectiveness of a small addition of a fourth element. As a result, we found that the effect of adding the fourth element depends on the periodicity in the periodic table, i.e. the chemical interaction with Zr, Cu and Al elements.

Formation and mechanical properties of Zr$z.sbnd;Cu$z.sbnd;Al bulk glassy alloys

We used highly purified elements (i.e. low-oxygen-content Zr metal) and a special arc melting and casting furnace to prepare Zr 50 Cu 40 Al 10 rod-shaped bulk glassy alloy over 10 mm in diameter. In the Zr-Cu-Al alloy system, we examined the glass-forming ability in the bulk glassy state by Δ T x , T g / T l , and the Hruby factor. The Hruby factor is appropriate for evaluating glass-forming ability in the cast Zr-Cu-Al bulk glassy alloy. In order to enhance the mechanical properties even in pre-oxidized Zr-Cu-Al (oxygen concentration 1000 ppm) bulk glassy alloy, we examined the effectiveness of a small addition of a fourth element. As a result, we found that the effect of adding the fourth element depends on the periodicity in the periodic table, i.e. the chemical interaction with Zr, Cu and Al elements.

Numerical simulation of airflow in the human nose.

Unobstructed air passageways as well as sufficient contact of the air stream with the mucous membrane are essential for the correct function of the nose. For that, local flow phenomena, which often cannot be captured by standard diagnostic methods, are important. We developed and validated a method for the numerical simulation of the nasal airflow. Two anatomically correct, transparent resin models of human nasal cavities, manufactured by a special casting technology, and the nasal cavities of two patients were reconstructed as Computer Aided Design models based on computed tomography (CT) scans. One of the nasal models and one clinical case represented a normal nasal anatomy, while the others were examples of pathological alterations. The velocity and pressure fields in these reconstructed cavities were calculated for the entire range of physiological nasal inspiration using commercially available computational fluid dynamics software. To validate the results rhinoresistometric data were measured and characteristic streamlines were videotaped for the resin models. The numerical results were in good agreement with the experimental data for the investigated cases. An example of a complex clinical case demonstrates the potential benefit of the developed simulation method for rhinosurgical planning. The results support the assumption that even under the specific conditions of the clinical practice the application of numerical simulation of nasal airflow phenomena may become realistic in the near future. However, important technical issues such as a completely automated reconstruction of the nasal cavity still need to be resolved before such simulations are efficient and cost effective enough to become a standard tool for the rhinologist.

The Presidency and the law: the Clinton legacy

Political scandals have always demonstrated the capacity of our executive officials for self-inflicted injuries, and the Clinton administration was no exception. Unilateral war-making, claims of executive privilege and immunity, and last-minute pardons all tested the limits of presidential power, while the excesses of the Special Prosecutor cast doubts on available remedies. For eight years, Republicans and Democrats engaged in guerrilla warfare aimed at destroying the careers and lives of their adversaries, while tests of presidential power were resolved by the courts, resulting in a reshaping of the scope and power of the presidency itself. This book examines the many controversial and important battles that led to the shrinking of the presidency under the law during the Clinton administration. Located at the intersection of law and politics, it helps readers understand the dramatic changes that took place in the relationship of presidential power to the law during the Clinton years and shows how one president's actions - and congressional and legal reactions to them - have altered presidential prerogatives in ways that his successors cannot ignore. The Presidency and the Law assesses changes in our constitutional and legal understanding of the American presidency, exploring such topics as war power, executive privilege, pardon power, impeachment, executive immunity, independent counsel, and campaign finance. In examining these collisions between the president and the law, its distinguished contributors bring the lessons of Watergate and Iran-Contra into the Clinton era and contribute to a Madisonian view that presidents should not operate outside statutory and constitutional constraints. Although quite critical in many respects, a number of these authors have been supportive of Clinton and his policy pursuits, and all seek to examine the potential impact of the Clinton administration without being predictive or legalistic. Still, under Bill Clinton's stewardship, the legal, constitutional, and political terrain changed in significant ways. It remains to be seen what impact these changes will have on the presidency in the twenty-first century. This book points the way to assessing that impact and is essential reading for anyone concerned with the future of our democracy.

Hot tearing in 319 alloy

To study the effect of strontium on hot tearing in 319 alloy, a special cast iron mould was made to produce a casting with “built-in” restraints that act to create tensile stresses along the length of the casting. Castings with different strontium additions and dissolved hydrogen concentrations were produced and evaluated using a hot tearing index. It was found that strontium has a beneficial effect in reducing hot tearing in 319 alloy. The underlying mechanism is related to the ability of strontium additions to redistribute macroshrinkage as fine internal porosity. The dissolved hydrogen concentration is a critical variable in hot tearing. As the hydrogen level increases, the tendency for hot tearing is reduced.

Processing of Cellular Magnesium Materials

Especially cellular aluminum materials have been extensively developed and investigated in the recent years. But also magnesium is a suitable metal for cellular metals due to its low density. By a special casting method open-cellular magnesium with a very low density of 0.05 g/cm3 is fabricated that shows high potential for usage as energy absorbers.

Photoelastic analysis of the singular stress field in a bimaterial wedge

This paper presents an experimental investigation of the singular stress field near the vertex of a bimaterial wedge using a digital photoelastic technique. Special attention is given to the casting of bimaterial wedge specimens and analysis technique for extracting stress intensity factors from photoelastic samples. Different bimaterial wedge specimens are made of two different photoelastic materials bonded through a special casting procedure and loaded in simple tension. A new multiple-parameter method is developed to obtain the stress intensity factor reliably from the isochromatic fringe patterns and the series representation of the stress field at the vertex of the wedge. Experimental results are compared with finite element predictions, and good agreement is observed.

Modeling the process of thermoelastoplastic deformation for calculating the distribution of residual stresses and strains

1. We have developed a thermomechanical model of recovery of worn parts of a void-cylinder type made of iron-carbon alloys by thermoelastoplastic deformation, which makes it possible to predict the stress-train state of the restored part theoretically. 2. The statement of problems of thermoelastoplasticity and their numerical realization by the method of finite elements with virtual coincidence of the calculated and experimental data has shown that the shrinkage of cylinder sleeves of tractor diesels with an internal diameter of 100–130 mm amounts to 0.7–1.2 mm over the diameter. 3. It is expedient to restore internal cylindrical surfaces, such as sleeves of cylinders of tractor engines produced from a special alloy cast iron, by creating a temperature gradient over the axis of the sleeve with heating and subsequent cooling of a local circular part of the cylinder. The heating is conducted to a temperature below that of the phase transformations (760–780°C). The optimum speed of displacing the inductor and the sprayer relative to the sleeve is 1–2 mm/sec.

Special features of warping of cast and welded parts at elevated temperatures under the action of residual temperatures

The regular features in warping of cast and welded parts produced from various alloys at elevated temperatures under the action of residual stresses are studied. The warping process under the action of residual stresses is directly reproduced on special cast and welded specimens. The temperature dependence of the warping is shown to behave similarly for various alloys and has an extremum at a specific temperature.

チタン・アルミ・タービン・ホイールの実用化

Present paper reported the first commercial application of titanium-aluminide (TiAl) in the world. TiAl is one of the heat-resistant light materials, which has low density and high specific strength at elevated temperatures. TiAl was applied to turbine wheel of turbocharger of commercial sport type vehicles. Mitsubishi Heavy Industries newly developed high performance turbocharger with TiAl turbine wheel which was produced by special precision casting process for reactive metals called LEVI-CAST. Weight reduction of the turbine wheel due to adaptation of TiAl improved transient response of turbocharger. The turbocharger passed continuous and thermal cyclic endurance test. Mitsubishi Motors Corporation adopted it for gasoline engine of Lancer Evolution VI(RS).

Maintenance of musculoskeletal function in people with haemophilia

Bleeding affecting muscles and joints is the most common manifestation of haemophilia. In the long term, prevention of musculoskeletal abnormality in haemophilic patients is cost effective. Early diagnosis and proper treatment is fundamental to prevent disability. Prevention can be divided into secondary and tertiary levels. Secondary prevention concentrates on how to handle a haemophilic child, and on the education of the family so that they develop a safe and healthy lifestyle and awareness of the importance of early diagnosis and treatment. Tertiary prevention deals with minimizing the musculoskeletal consequences of muscle and joint bleeding. Coagulation factor replacement, appropriate care of the bleeding site and early physical therapy helps to prevent complications and yields the best results. Recurrent episodes of joint bleeding can lead to chronic synovitis. Initially synovitis demands conservative treatment. However, conservative methods are often not successful. Chronic synovitis is the most important cause of joint degeneration and the aim of rehabilitation is to achieve functional status using special casting techniques, orthoses or preventative surgery. Surgical, radioisotope or chemical synovectomy may be used. Technical requirements and availability of haemostatic cover limit the use of surgical and radioisotope synovectomy. The author has found chemical synovectomy with rifampicin to be an easier and more effective procedure than surgery. Problems related to joint deformities, muscle atrophy and chronicle pain demand comprehensive care. They are the main factors affecting the maintenance of musculoskeletal function and the social integration of people with haemophilia.

Complete Subtalar Release in Resistant Clubfeet: A Critical Analysis of Results in 146 Cases

A series of 101 patients (146 feet) with resistant clubfoot corrected by complete subtalar release is presented. A detailed rating system was used to evaluate the results. Minimum follow-up was 2 years. Fourteen feet (9.6%) had undergone additional surgical procedures at the time of review, and 101 feet (69%) had excellent or good functional ratings at that time. The mean total ankle motion was 34.2 degrees (range, 8-56 degrees). The better results occurred in feet without previous surgery. Final ankle range of motion was increased by using a special flexed-knee cast with reserve space above the foot. Longer follow-up is needed to determine the optimal age for surgery.

Daura and gender in the creation of a Hausa national epic

Summary Beginning with the story as it was told in the Sokoto Caliphate in the first half of the nineteenth century we illustrated the narrative's practical political value within the context of the Sokoto's relationships with the newlyconquered Hausa, and also presented it in the form in which it was first transmitted to Europeans. Not until the early decades of the twentieth century would variations of the Daura narrative influenced by the cultural and political relationships between the eastern Hausa kingdom of Kano and the neighbouring Kanuri empire of Bornu come to the attention of Europeans. The texts from eastern Hausa sources also revealed aspects of the Hausa's Islamic cultural literacy. Finally, a unique and highly divergent telling of the narrative, created by a Kano‐educated Islamic scholar in the early years of the twentieth century, shifted the story out of either the equally Islamic Sokoto and Bornu intellectual traditions and reasserted its fundamental relationship to pre‐Islamic Hausa ora...

Experimental analysis of an arbitrarily inclined semiinfinite crack terminated at the bimaterial interface

In this paper, the digital photoelastic technique was employed to investigate the effect of different material combinations and different crack inclination angles on the stress-intensity factors (SIFs). To produce a true bimaterial plate, the two component materials were naturally adhered together by a special casting procedure. The experimental results show that dimensionless combined SIF increases with increasingG1/G2 (or crack inclination angles) for different crack inclination angles (orG1/G2's).

The Jackfield Bridge, Ironbridge, UK

This article briefly describes the planning, design and construction of the cable-stayed Jackfield Bridge, which is the new neighbour of the world bridge famous Iron Bridge and several other historic bridges in the Iron Bridge Gorge, Shropshire, England. The unusual and striking design is the result of national debate and a Public Inquiry. Located 1 km downstream of the Iron Bridge, it is in the centre of the Severn Gorge World Heritage Site. The Jackfield Bridge uses composite steel and concrete sections for both the tower and the deck, which is supported from the tower by high tensile locked coil ropes. Special steel casting, bearings and parapets were designed for the bridge.

An Emergency Stop Device for a Super High Speed Elevator(810m/min)(Development of Braking Materials).

A braking material for an emergency stop device for a super high speed elevator (810 m/min)was developed. The material is a special cast iron containing Cr, Ni and P. Its structure is a pearlitic matrix of flaky graphite, steadite and cementite, and its wear resistance is about lO times that of FC250. Its coefficient of friction is about 1. 5 times that of FC250. A new emergency stop device made of the material was proven to conform to Japanese standards and ANSI (American National Standards Institute) standards for stopping-distance and car inclination criteria in tests conducted by dropping actual-scale equipment.