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Abstract The friction characteristics of a shock absorber are very complex because the reciprocating motion is not always identical. In this study a device was developed and used to analyze the dynamic friction characteristics under various reciprocating sliding conditions to determine the sliding materials and hydraulic oils that improve the shock absorber performance. This study describes the influence of hydraulic oil additive on the fine reciprocating friction characteristics of steel and copper alloy. Hydraulic oils were prepared by blending a paraffinic mineral oil with zinc dithiophosphate (ZnDTP) and polyhydric alcohol ester as additives. The results show that the dynamic frictional characteristics vary mainly depending on the additive concentration. A specific additive formulation induces a unique amplitude-dependent friction behavior. In addition, the influence of different additives on the lubrication mechanism is investigated based on the instrumental analysis of the friction surface.

Background:. Damage and loss of ear cartilage can easily occur in a burned ear accompanied by severe extensive burns due to exposure of the cartilage or chondritis. Deformity can also occur due to later development of scar contracture despite minimal damage to the ear cartilage when the injury occurred. We have developed a new technique for treatment of a deep burn in the whole ear. Methods:. In the new technique, the ear is amputated, and soft tissues are denuded. The cartilage is banked in a subcutaneous pocket in the chest and later regrafted in combination with costal cartilage. Results:. Although techniques for regrafting banked ear cartilage have been reported, the reconstructed ear cannot acquire a good shape because of absorption of the cartilage or lack of intensity to sustain the outline of the ear. Meanwhile, when we tried to reconstruct an ear by only using costal cartilage, we found it difficult to fabricate a frame because most patients are adults in whom the costal cartilage is too rigid and fragile to be shaved or combined. In our technique, the frame has both the advantages of sufficient intensity in costal cartilage and a smooth curved surface together with elasticity in the ear cartilage. Ears reconstructed by our technique have a natural appearance. Conclusion:. Our technique can be used for cases in which treatment for another large area of the body surface needs to be performed first to save the patient’s life.

Background:. Problems with poor circulation often occur when a large defect or a distant region, such as the apex of the nose, is covered with a paramedian forehead flap. Delay technique increases the safety of reconstruction procedures, but it has been used less frequently because a 2-stage surgery is necessary, and various other flaps and techniques have been developed. Method:. We performed the delay technique of paramedian forehead flap at the same time as tumor resection. For the flap, a narrow pedicle of about 1-cm was prepared on the supratrochlear artery and vein, and the incision was extended toward the lateral side conforming to the defect morphology, and a paramedian forehead flap with a design consistent with the esthetic unit containing the defect was prepared. The region below the flap was dissected to create the flap bipedicle, and surgery was completed. Result:. This procedure was used in 4 patients with malignant tumor of the external nose, and the flap survived perfectly in all patients. The postoperative esthetic outcome was also found to be good. Conclusions:. This procedure does not increase the frequency of surgery, circulation in the flap is maintained, the flap pedicle on the supratrochlear artery can be made narrow, and flap thinning can be performed from the beginning. Coverage of an extensive defect is possible because a large flap can be excised, and satisfactory esthetic appearance can be obtained by matching with the esthetic unit. The delay technique for various flaps (not limited to forehead flap alone) should be considered an effective technique for the current treatment of malignant tumors.

Background:. We have already reported surgical procedures for lobule-type microtia that provide an excellent contour and shape of the ear with minimum sacrifice of the donor. We have succeeded in establishing a standard surgical technique for almost all types of concha-type microtia that effectively uses the remnant ear and can use a unified costal cartilage frame. Methods and Results:. The concept of our technique is that remnant cartilage should be used maximally but that the deformed area should be completely replaced by the costal cartilage frame. The differences between the cartilage frame for lobule-type microtia and that for concha-type microtia are that the lower half beneath the antihelical area and the concha cymba in the base frame are omitted in concha-type microtia. The area from the tragus to the incisura of the tragus in the antihelical-tragal frame is also omitted. The area of the helical crus in the helical frame and the lower half in the antihelix are not immobilized in the base frame and are free edges. On the other hand, the remnant cartilage outside the concha is removed, but the antitragus is preserved. When the cartilage frame and the remnant are incorporated, all of the components of the ear can be provided. Conclusion:. The ears created by our technique have a natural appearance and clear contour.

3 different base-stocks (poly-α-olefin, polypropylene glycol and unsaturated TMP ester) and additionally formulations with 2 different additives (1 mass% ZnDTP or 1 mass% dibenzyl disulfide (DBDS)) were used as lubricants to evaluate the tribological properties of A6061-T6 treated by means of plasma electrolytic oxidation in a SRV tribometer (Toil = 80°C, FN = 50 N, ν = 50 Hz, 2 mm stroke, 2 hrs). The base oils of PPG and the TMP-ester had better lubricities than the PAO with/without the additives. ZnDTP tend to reduce wear, but when added to PAO and PPG increased the friction. The unsaturated TMP-ester +1 mass% DBDS showed 45% lower friction than PAO + ZnDTP (reference), whereas PPG + DBDS had 30% lower friction.

Background: Here, we introduce our recent operative technique for ear elevation that results in (1) minimal morbidity for patients, (2) symmetric appearance, (3) clearer 3-dimensional structure with a deep concha, (4) good aesthetic appearance by hiding the grafted area behind the ear, and (5) maintenance of deep temporoauricular sulcus and angle. Methods: After a skin incision, the ear is elevated with temporoparietal fascia underlying the cartilage. On the conchal area, undermining is performed just below the skin so that the deep concavity can be maintained. Scalp and neck skin behind the ear is undermined subcutaneously and lifted up cranially to hide the entire area of grafted skin behind the ear. The postauricular surface is covered by full-thickness skin from the lower abdomen. A protective splint is applied for 3 months while sleeping. Results: A total of 137 ears in 121 patients were corrected with our technique and followed up for at least 3 years. All of the scar tissue could be hidden behind the ear, an aesthetically excellent result. Conclusions: Our technique made it possible to acquire an excellent and symmetrical shape of the ear. The important points in our procedure are as follows: (1) subcutaneous posterior undermining to enlarge the conchal cavity, (2) careful arrangement of the temporoauricular angle and auriculo-earlobe angle, (3) reduction in the area of temporally grafted skin to hide all scars behind the ear, and (4) protection of the ear to maintain the shape using a postoperative splint.

Volume and issue: Vol. 10 , No. 1 (2015)Page: pp. 56-63Title: Lubricities of Environmentally Acceptable Lubricants with Zinc Dialkyldithiophosphate and Dibenzyl Disulfide on Tribological Properties of Plasma Electrolytic Oxidation Coated A6061-T6 Alloy under Mixed/Boundary LubricationAuthor(s): Takuya Nakase, Shinji Kato, Mathias Woydt, Shinya Sasaki