A Flow Sensing Device Formed Exclusively by Employing Additive Manufacturing for On-Site Fabrication Aboard a Ship.

This work concerns the design, fabrication, and testing of a novel air-flow sensor employing exclusively additive manufacturing that can be fabricated on-site, aboard a ship, or in a similarly remote area, without relying on external manufacturing facilities. The developed device's principle of operation is based on vortex shedding; its novelty focuses on employing solely additive manufacturing technology, for the manufacturing-in a single process step-of all the sensor's main elements. In more detail, the required flow-shaping housing, the appropriate piezoresistive sensing element, and the electrical interconnection pads are all constructed in a single process step, through standard Fused Deposition Modeling (FDM) 3D technology. Direct communication to the necessary readout circuitry can be easily achieved through standard soldering utilizing the integrated contact pads of the sensor. The prototype was preliminary characterized, validating its proper functionality. Key features of the proposed device are low cost, fast on-site manufacturing of the entire measuring device, robustness, and simplicity, suggesting numerous potential applications in the shipbuilding industry and other industrial sectors.

Spare Parts Demand Forecasting Method Based on Intermittent Feature Adaptation.

The demand for complex equipment aftermarket parts is mostly sporadic, showing typical intermittent characteristics as a whole, resulting in the evolution law of a single demand series having insufficient information, which restricts the prediction effect of existing methods. To solve this problem, this paper proposes a prediction method of intermittent feature adaptation from the perspective of transfer learning. Firstly, to extract the intermittent features of the demand series, an intermittent time series domain partitioning algorithm is proposed by mining the demand occurrence time and demand interval information in the series, then constructing the metrics, and using a hierarchical clustering algorithm to divide all the series into different sub-source domains. Secondly, the intermittent and temporal characteristics of the sequence are combined to construct a weight vector, and the learning of common information between domains is accomplished by weighting the distance of the output features of each cycle between domains. Finally, experiments are conducted on the actual after-sales datasets of two complex equipment manufacturing enterprises. Compared with various prediction methods, the method in this paper can effectively predict future demand trends, and the prediction's stability and accuracy are significantly improved.

The Demand Supply Steady-State Process-Based Multi-Level Spare Parts Optimization.

Spare parts are one of the important components of the equipment comprehensive support system. Spare parts management plays a decisive role in achieving the desired availability with the minimum cost. With the equipment complexity increasing, the price of spare parts has risen sharply. The traditional spare parts management makes the contradiction between fund shortage and spare parts shortage increasingly prominent. Based on the analysis of the multi-echelon and multi-indenture spare parts support model VARI-METRIC (vary multi-echelon technology for recoverable item control, VARI-METRIC), which is widely used by troops and enterprises in various countries, the model is mainly used in high system availability scenarios. However, in the case of low equipment system availability, the accuracy and cost of model inventory prediction are not ideal. This paper proposed the multi-level spare parts optimization model, which is based on the demand-supply steady-state process. It is an analytical model, which is used to solve the low accuracy problem of the VARI-METRIC model in the low equipment system availability. The analytical model is based on the multi-level spare parts support process. The article deduces methods for solving demand rate, demand-supply rate, equipment system availability, and support system availability. The marginal analysis method is used in the model to analyze the spare parts inventory allocation strategy's current based cost and availability optimal value. Finally, a simulation model is established to evaluate and verify the model. Then, the simulation results show that, when the low availability of equipment systems are 0.4, 0.6, the relative errors of the analytical model are 3.54%, 3.86%, and its costs are 0.52, 1.795 million ¥ RMB. The experiment proves that the inventory prediction accuracy of the analytical model is significantly higher than that of the VARI-METRIC model in low equipment system availability. Finally, the conclusion and future research directions are discussed.

Partial Calcaneus Reconstruction using 'Opportunistic Grafts': A Case Report.

Although replantation of an amputated extremity has been successfully performed, occasionally the surgeon is forced to amputate in the case of an unsalvageable open fracture. These appendages can theoretically act as an autologous 'bone and tissue bank' for patients if they have reconstructable contralateral injuries. We present a case of an athlete who sustained a Gustilo and Anderson IIIC injury on 1 leg resulting in a below knee amputation. Her other lower leg had a traumatic amputation of the heel pad, partial amputation of the calcaneus, and complete Achilles tendon loss. Tissues from this amputated appendage were utilised to restore the anatomy of the contralateral extremity. The distal tibia and the tibialis anterior from the amputated limb were used to reconstruct the missing posterior tuberosity of the calcaneus and the Achilles tendon respectively. The soft tissue deficiency of the heel pad was restored with an anterolateral thigh free flap. At 2-year follow-up, the patient is pain free and back to playing soccer. This case highlights the opportunistic use of amputated parts to reconstruct a calcaneus and Achilles tendon. A multidisciplinary approach with plastic surgeons is required. The main advantage of this 'Spare Part Surgery' philosophy is to provide autologous graft of a similar geometry and to avoid harvesting tissues from an additional donor site.

Avoiding Above-the-Knee Amputation with a Free Tibiofibular-Talocalcaneal Fillet Flap and Free Latissimus Dorsi Flap.

Despite the advances achieved in reconstructive surgery, amputation is still the only option after some severe traumas. Preservation of the knee joint is considered a significant functional advantage. We present the case of a 39-year-old man with a comminuted Gustilo type IIIC open tibia fracture with massive bone loss. To achieve a well-fashioned amputation stump and preserve the knee joint, a free osteocutaneous fillet flap was performed, including the distal tibia and fibula, talus, and calcaneus bones. As a result, a sensate and long amputation stump covered with thick skin from the sole of the foot provided a stable coverage with an excellent functional result and adjustment to prosthesis.

Chimeric Free Vascularized Metatarsophalangeal Joint With Toe Fillet Flap: A Technique for Reconstruction of the Posttraumatic Metacarpophalangeal Joint With Concomitant Soft Tissue Defect.

For painful, dysfunctional, posttraumatic metacarpophalangeal (MCP) joints, the free vascularized toe joint transfer may represent a good solution. Successful reconstruction is potentially limited, however, by 2 features of the traditional vascularized metatarsophalangeal (MTP) transfer: inadequate arc of flexion and insufficient soft tissue coverage. The solution to both of these dilemmas lies in the manner of utilizing the donor site. Because of its innate hyperextensibility, rotating the MTP 180° volar to dorsal provides the greatest arc of flexion in the reconstructed MCP. Excellent soft tissue coverage can be provided by elevating the skin paddle of the transferred second toe as a chimeric fillet flap, based on the tibial plantar digital artery.

[Spare-parts concept in pediatric hand: About one bilateral syndactyly]. / Principe du doigt-banque en main congénitale : à propos d'une syndactylie bilatérale.

INTRODUCTION: The spare-parts concept is well described in traumatology of the hand. Tissues of a scarified ray are used to reconstruct another damaged finger. We will detail an application in pediatric hand through a clinical case. MATERIALS AND METHOD: We describe a patient presenting a bilateral complete and non-complex syndactyly of the third web space associated with a bilateral hexadactyly classified as type B according to the Temtamy and Mc Kusick's classification. The treatment of the syndactyly was performed with a dorsal flap for the web space and with longitudinal zigzag incisions in mirror. Skin loss of the lateral sides of the fingers was covered by the full-thickness graft taken on the supernumerary finger which was treated in the same surgical time. DISCUSSION: This application of the spare-parts concept allows only one surgical site with absence of scar on the donor site and a skin graft close to the skin loss on the finger. CONCLUSION: The spare-parts concept can be applied in some cases of pediatric hand and must be a tool for the surgeon.

Transplantation of a free fillet flap from discarded fingers for repair of a finger pulp skin defect: a case report.

Background: Replantation represents a treatment option for patients with severed finger pulps. However, in some cases, replantation is a challenging task. Case presentation: We report a successful case of finger pulp reconstruction of the ring finger using free flaps from a nonreplantable index finger in a spare-parts procedure. A 43-year-old worker accidentally injured the index, middle and ring fingers of his left hand on a machine turntable. The severed index and middle fingers and the distal pulp of the ring finger could not be replanted in situ due to extensive contusion of blood vessels and soft tissues. After vascular and nerve anastomosis, a free skin flap isolated from the nonreplantable index finger was transplanted to the wound of the distal pulpal defect of the ring finger. The flap survived completely postoperatively. Six months after the operation, only a slight deformity of the ring finger was observed. Moreover, sensation of the digit recovered well. Conclusions: Spare-part surgery is a surgical approach that effectively saves and utilizes tissue that would otherwise be discarded in cases of severe limb trauma. This idea may be applied to treatment of severe injuries to multiple fingers. Additionally, in the process of tissue transplantation and repair, attention should be given to protecting the tissue in the recipient area to avoid damage to the original undamaged tissue structure, which can adversely affect healing and recovery of the tissue.

Double flap from amputated opposite lower limb for cover of plantar and dorsal surfaces of a crushed foot.

Bilateral limb trauma poses many possibilities for management. In a situation of bilateral amputation, if the amputated limb is not salvageable or replantation is not advisable, the amputated limb can be used to harvest tissue for free tissue transfer to cover the amputation stump. We describe a case here in which we have used these principles.

Influence of 3D printing properties on relative dielectric constant in PLA and ABS materials.

Nowadays, it is well known that on the ship, free space is at a premium. Unfortunately, every part on the ship has its duration before the failure, and the spare parts occupy the space. The broken part must be replaced when the failure occurs to maintain the ship's operation. Developing 3D printer technology and particular material technology, it has become possible to print a spare part that can replace broken. However, due to hazardous environments (salt, humidity, vibrations, etc.), printed parts change their properties. Electrical capacity and further dielectric permittivity is a parameter or metric that has to be monitored since it directly influences the printed part material structure. Therefore, this paper aims to research the impact of relative dielectric constant in additive manufacturing on printed ship's spare parts since infill patterns and density were changed due to a hazardous environment. The experiment, in which the three shaped material samples are created, consists of the following equipment, the Ultimaker S5 3D printer, Polylactic Acid (PLA) and Acrylonitrile-Butadiene-Styrene (ABS) materials, and LC HM 8018 m. Results show relative dielectric constant changes between 1.7778 and 2.8141 for PLA and between 2.1979 and 2.9989 for ABS, depending on infill density and pattern. ANOVA test for ABS is performed to investigate how the calculated dielectric constant relates to the infill density for various infill shapes. Scores are: F = 154.3773, Fcrit = 5.1432, and p = 6.9269·10-6. ANOVA test for PLA resulted in scores F = 18.911, Fcrit = 5.1432, and p = 0.0022.

"Spare Parts" for Foot Wound Reconstruction: A Report of 2 Cases.

Soft tissue reconstruction of the foot can be a complex task to undertake when presented with challenging wounds. The foot comprises thick, glabrous skin with its own unique soft tissue anatomy that is suited to withstand its necessary functional demands. "Spare parts" reconstruction provides an option for closure of complicated skin wounds encompassing areas of large, unsalvageable defects. This report presents the cases of 2 patients who underwent successful care at our institution. Each patient's approach was individualized based on the etiology and presentation of the wound while any comorbid conditions were taken into consideration. The purpose of these case reports is to highlight 2 examples involving spare parts foot reconstruction of complicated defects, both of which decreased donor morbidity and lessened the degree of amputation.

Preventing biological waste: Effective use of viable tissue in traumatized lower extremities.

Severe open lower extremity trauma requires debridement to remove contamination and devitalized tissues. Aggressive debridement should be balanced with preservation of viable tissue. These often damaged but preserved viable tissues are "spare parts" that augment the options available for reconstruction. The long-term goal of reconstruction should be functional limb restoration and optimization. Injury patterns, levels, and patient factors will determine whether this endeavor is better accomplished with limb salvage or amputation. This article reviews the rationale and strategies for preserving spare parts throughout debridement and then incorporating them as opportunistic grafts in the ultimate reconstruction to facilitate healing and maximize extremity function. Level of Evidence: 5.

Osteocutaneous Turn-Up Fillet Flaps: A Spare-Parts Orthoplastic Surgery Option for a Functional Posttraumatic Below-Knee Amputation.

This article portrays the authors' experience with a complex lower limb bone and soft tissue defect, following chronic osteomyelitis and pathological fracture, which was managed by the multidisciplinary orthoplastic team. The decision for functional amputation versus limb salvage was deemed necessary, enhanced by the principles of "spare parts" in reconstructive microsurgery. This case describes the successful use of the osteocutaneous distal tibia turn-up fillet flap that allowed "lowering the level of the amputation" from a through knee to a below-knee amputation (BKA) to preserve the knee joint function. We comprehensibly review reports of turn-up flaps which effectively lower the level of amputation, also applying "spare-parts" surgery principles and explore how these concepts refine complex orthoplastic approaches when limb salvage is not possible to enhance function. The osteocutaneous distal tibia turn-up fillet flap is a robust technique for modified BKA reconstructions that provides sufficient bone length to achieve a tough, sensate stump and functional knee joint.

Pedicled hand fillet flap to preserve stump length in below-elbow amputation.

Spare-parts surgery in traumatic amputation sources tissue from the amputated part to cover the residual amputation defect. This case describes a trauma patient requiring below-elbow amputation. Stump closure was accomplished with a pedicled fillet flap derived from the still-attached hand, avoiding donor site morbidity and maximizing stump length.

Defect Coverage after Forequarter Amputation-A Systematic Review Assessing Different Surgical Approaches.

Autologous fillet flaps are a common reconstructive option for large defects after forequarter amputation (FQA) due to advanced local malignancy or trauma. The inclusion of osseous structures into these has several advantages. This article therefore systematically reviews reconstructive options after FQA, using osteomusculocutaneous fillet flaps, with emphasis on personalized surgical technique and outcome. Additionally, we report on a case with an alternative surgical technique, which included targeted muscle reinnervation (TMR) of the flap. Our literature search was conducted in the PubMed and Cochrane databases. Studies that were identified were thoroughly scrutinized with regard to relevance, resulting in the inclusion of four studies (10 cases). FQA was predominantly a consequence of local malignancy. For vascular supply, the brachial artery was predominantly anastomosed to the subclavian artery and the brachial or cephalic vein to the subclavian or external jugular vein. Furthermore, we report on a case of a large osteosarcoma of the humerus. Extended FQA required the use of the forearm for defect coverage and shoulder contour reconstruction. Moreover, we performed TMR. Follow-up showed a satisfactory result and no phantom limb pain. In case of the need for free flap reconstruction after FQA, this review demonstrates the safety and advantage of osteomusculocutaneous fillet flaps. If the inclusion of the elbow joint into the flap is not possible, we recommend the use of the forearm, as described. Additionally, we advocate for the additional implementation of TMR, as it can be performed quickly and is likely to reduce phantom limb and neuroma pain.

Dynamic repair priority rule based on remaining useful life predictions.

In this paper, we propose a novel repair priority rule for spare parts in a repair station with limited repair capacity to minimize total inventory cost per time unit. Inventory cost is composed of holding costs and backorder costs. The proposed rule uses Remaining Useful Life (RUL) predictions of functioning machines obtained from a Prognostics and Health Monitoring (PHM) system. An inventory system comprising a finite number of machines, one warehouse, and one single-server repair station is considered. Numerical experiments were conducted to compare the performance of the proposed model with the performance of three existing priority rules: a first-come, first-served (FCFS) rule, a static priority rule, and a dynamic priority rule. A testbed with 20 instances of the problem was considered. The results showed that the proposed PHM-based rule consistently reduces the inventory system cost.

Classification and clinical evaluation of "spare parts" procedures in mutilating hand injuries.

Mutilating hand injuries are common, and reconstruction should be tailored to each case. The "spare parts" concept relies on harvesting tissues for reconstruction from amputated or non-salvageable parts that are being discarded. This study sought to evaluate the outcomes of "spare parts" procedures in mutilating hand injuries and to propose a classification of "spare parts" types. This study included 28 patients with mutilating hand injuries undergoing surgery using "spare parts" for tissue reconstruction either at the time of trauma or later on. A total of 31 "spare parts" procedures were performed on the 28 patients. The outcomes were assessed in terms of reconstruction success, Disabilities of the Arm, Shoulder, and Hand (DASH) score, grip strength, and an overall patient satisfaction score that we designed. Reconstruction using "spare parts" was successful in 25 patients (89%). The mean DASH score was 8.45 ± 4.74, the mean grip strength was 24.57 ± 2.73 kg, and overall patient satisfaction was 3.32 ± 0.77 out of 5. Specific outcomes were assessed using case-specific measures. Based on these data, a hand-specific classification of "spare parts" procedures was designed to be taken into consideration when managing mutilating hand injuries. Besides direct digital replantation and tissue harvesting from different donor sites, the "spare parts" concept is an important tool for a hand surgeon. Its different types should always be taken into consideration when managing mutilating hand injuries to avoid additional donor site morbidities and to achieve a high level of overall patient satisfaction. We propose adding a "patient satisfaction with hand appearance" item to the DASH and QuickDASH score.

Microsurgical reconstruction of congenital upper extremity deformities of malformations.

We present two rare microsurgical reconstructions. A case with phocomelia was treated with lengthening of soft tissues following vascularized fibula grafting with epiphysis, and a case with cleft hand was reconstructed with spare-part toe transfer.

Preservation of lower extremity spare parts using the University of Wisconsin solution.

The management of a mangled limb is a challenging endeavor. With the advancement in microsurgery, spare parts surgery (fillet flaps) has gained recent interest. In the context of lower extremity amputation secondary to trauma, viable spare parts can provide stump soft tissue coverage, potentially preserving critical length and obviating above-knee amputations. Commonly, spare parts surgery is performed in the acute setting but tissue preservation is sometimes necessary. The authors report their experience preserving a fillet flap of a mangled lower extremity for 48 h using the University of Wisconsin solution. A sole fillet flap and a split-thickness skin graft were harvested and preserved from the amputated lower extremity (based on the posterior tibial artery and vein). Stump coverage was achieved by anastomosing the fillet flap to the proximal posterior tibial artery and vein. This solution has not been previously described for preservation of fillet flaps.

Assessment of the Potential Economic Impact of the Use of AM Technologies in the Cost Levels of Manufacturing and Stocking of Spare Part Products.

Additive manufacturing (AM) technologies are appropriate manufacturing technologies to produce low rotation products of high added value. Products in the spare parts business usually have discontinuous demand levels of reduced numbers of parts. Indeed, spare parts inventories handle myriad of products that require big immobilized investments while having an intrinsic risk of no-use (for example due to obsolescence or spoilage). Based on these issues, the present work analyses the fundamental cost factors in a real case study of a company dedicated to the supply of spare parts for fluid conduction systems. Real inventory data is assessed to determine the product taxonomy and its associated costs. A representative product of the stock is analyzed in detail on original manufacturing costs, in AM costs and then redesigned with topological optimization to reduce the AM cost levels (via design for additive manufacturing). A general equation for cost assessment is formulated. Given the specific data collected from the company, the parameters in this general equation are calculated. Finally, the general equation and the product cost reduction achieved are used to explore the potential economic impact of the use of AM technologies in the cost levels of manufacturing and stocking of spare part products.