impact of merging components by additive manufacturing in spare parts management

Abstract This paper investigates impacts of merging components and reduction of sub-assemblies by exploiting additive manufacturing (AM) capabilities to allow for production of various components forming the final part composition as just one single part. The analysis is performed by considering a base structure for part composition, and inclusion of final components currently produced with conventional methods, and then comparing this with a list of alternatives that consist of merged components realized through AM. The comparative analysis among three main factors of reliability, logistics, and production cost and their impacts over average expected cost are the main aims of this study

On how the acquisition of recoverable parts influences the profitability of spare parts management for durables

In the management of spare parts for durables OEMs often face a sharp decline in sales of spare parts when the warranty period of their products ends. One reason for this effect is given by the high profitability of the after sales market which attracts competitors. If the competitors\u27 main sourcing option consists of repairing used or broken parts, an acquisition of those parts by the OEM might lower competition and increase sales. The purpose of this paper is to provide a case-based framework to offer insights on the opportunity of recovering parts. We consider a two-stage supply chain, where independent repair shops are responsible for handling the repair process. There are two options to meet spare parts demand: repair shops may replace the part with a new one (ordered from the OEM) or they may use a part that they repaired before. While repair shops achieve a larger profit by repairing parts, the OEM would prefer the use of new parts. However, he has no control on demand which might be obtained through buyback of broken parts. Furthermore, the OEM could recover these parts on a higher level, thus reducing production/procurement of new parts. The main contribution of this paper is to elaborate the important effects of recoverable items acquisition on spare parts demand by using a simple deterministic framework thus outlining the impact of different parameters on the profitability of spare parts management

Benefits and costs of additive manufacturing applications: an evaluation guideline

With an ever growing diffusion of additive manufacturing (AM) system in industrial and consumer level, as well as the direct and indirect dynamics which are being introduced resulting from its inclusion as a viable production system on companies’ portfolio, the need to reconfigure production system and adapt the production line becomes even more relevant than before. There are several studies which have emphasized on the importance of a paradigm shift in order to exploit advantages of AM, not only considering design and functionality of the product but also with regards to its impact on the entire value chain reconfiguration. Thus, it is of crucial importance to take into consideration that for this shift to be feasible and manageable, it needs to include both technical and managerial aspects of manufacturing. This work proposes a new perspective to provide a guideline for the proper evaluation of AM implementation from a holistic viewpoint. Starting from a priori analysis, the authors provide a three-steps evaluation guideline, thanks to which companies interested in additive manufacturing could verify both technical and economical feasibility of its implementation, comparing it to the conventional subtractive techniques. The proposed guideline is tested in real case study, which the main results are shown in section 5

Effects of dislocation density on injection and temperature sensitivity of InGaN LED emission spectra: a combined experimental and simulation approach

The aim of this paper is to describe a combined simulation and characterization activity carried out on blue LEDs grown on templates with different threading dislocation densities (TDDs)

Effects of Energy Efficiency Measures in the Beef Cold Chain: A Life Cycle-based Study

Abstract Circular economy and industrial symbiosis represent a production and consumption model involving sharing, lending, reusing, and recycling existing materials and products in the most efficient way to increase sustainability and reduce or eliminate waste. Beef production has a high impact on the environment in different impact categories, especially those activities related to livestock breeding and feeding. In this study, a life cycle assessment and a life cycle cost evaluation are carried out investigating potential energy efficiency measures to promote industrial symbiosis scenarios referring to a proposed baseline scenario. Three main potential measures are evaluated: energy recovery from waste via anaerobic digestion, integration of renewable sources at warehouses, including solar PV panels, and the replacement of auxiliary equipment at the retailer. It was found that energy reconversion of food waste through anaerobic digestion and cogeneration provides the most valuable benefits to the supply chain. From the economic perspective, using a conventional life cycle cost assessment, the energy production from the use of wastes for anaerobic digestion proved to be the best potential option

patients with hypertensive nephropathy and chronic kidney disease might not benefit from strict blood pressure control

Background/Aims: In patients with chronic kidney disease (CKD) strict blood pressure (BP) control is reno-protective. However, renal benefits from BP control might depend also on the etiology of CKD. We investigated if maintenance of BP at target is equally effective in subjects with hypertensive nephropathy (HN+) and in those with other nephropathies (HN-). Methods: We evaluated 148 patients with CKD (stages 3-5) in two visits at least 12 months apart. BP was measured both as office BP and 24h ambulatory blood pressure (ABP). Glomerular filtration rate (eGFR) was estimated with CKD-EPI formula. The slope of eGFR variation (ΔeGFR) was calculated as: (eGFR1-eGFR0)/months of follow up. Results: Cohort characteristics were: HN-(n=82) and HN+ (n=66), age (71±9 vs 74±9 years; p=0.09); prevalence of diabetes (57 vs 43%; p=0.19); average follow up (19±7 vs 21±9 months; p=0.3). HN- and HN+ did not differ regarding both baseline eGFR (34±18 vs 35±14 ml/min; p=0.97) and ΔeGFR (0.00±0.53 vs -0.06±0.35 ml/min/month, p=0.52). The proportion of patients with BP at target at both visits was similar in HN- and HN+ (office BP: HN- 18% and HN+ 27%; p=0.21; ABP: HN- 42% and HN+ 43; p=0.96). In patients with office BP at target at both visits HN- showed a significant improvement of ΔeGFR respect to HN+ (HN-: 0.240 ± 0.395 and HN+: -0.140±0.313 ml/min/ month; p=0.026). In patients with office BP not at target HN- and HN+ did not show any difference in ΔeGFR (HN- 0.00±0.47; HN+ -0.030±0.420 ml/min/month; p=0.66). ABP was not associated with differences in ΔeGFR either if it was at target (HN- 0.104±0.383 and HN+ 0.00±0.476 ml/min/month; p=0.42) or not (HN- -0.057±0.503 and HN+ -0.092±0.325 ml/ min/month; p=0.87). Conclusion: In patients with CKD and HN+ maintenance of BP targets recommended by current guidelines is less reno-protective than it is in HN-

Moderate and Severe Congenital Heart Diseases Adversely Affect the Growth of Children in Italy: A Retrospective Monocentric Study

: Children with congenital heart disease (CHD) are at increased risk for undernutrition. The aim of our study was to describe the growth parameters of Italian children with CHD compared to healthy children. We performed a cross-sectional study collecting the anthropometric data of pediatric patients with CHD and healthy controls. WHO and Italian z-scores for weight for age (WZ), length/height for age (HZ), weight for height (WHZ) and body mass index (BMIZ) were collected. A total of 657 patients (566 with CHD and 91 healthy controls) were enrolled: 255 had mild CHD, 223 had moderate CHD and 88 had severe CHD. Compared to CHD patients, healthy children were younger (age: 7.5 ± 5.4 vs. 5.6 ± 4.3 years, p = 0.0009), taller/longer (HZ: 0.14 ± 1.41 vs. 0.62 ± 1.20, p < 0.002) and heavier (WZ: -0,07 ± 1.32 vs. 0.31 ± 1.13, p = 0.009) with no significant differences in BMIZ (-0,14 ± 1.24 vs. -0.07 ± 1.13, p = 0.64) and WHZ (0.05 ± 1.47 vs. 0.43 ± 1.07, p = 0.1187). Moderate and severe CHD patients presented lower z-scores at any age, with a more remarkable difference in children younger than 2 years (WZ) and older than 5 years (HZ, WZ and BMIZ). Stunting and underweight were significantly more present in children affected by CHD (p < 0.01). In conclusion, CHD negatively affects the growth of children based on the severity of the disease, even in a high-income country, resulting in a significant percentage of undernutrition in this population

An Exploratory Study of Field Failures

Field failures, that is, failures caused by faults that escape the testing phase leading to failures in the field, are unavoidable. Improving verification and validation activities before deployment can identify and timely remove many but not all faults, and users may still experience a number of annoying problems while using their software systems. This paper investigates the nature of field failures, to understand to what extent further improving in-house verification and validation activities can reduce the number of failures in the field, and frames the need of new approaches that operate in the field. We report the results of the analysis of the bug reports of five applications belonging to three different ecosystems, propose a taxonomy of field failures, and discuss the reasons why failures belonging to the identified classes cannot be detected at design time but shall be addressed at runtime. We observe that many faults (70%) are intrinsically hard to detect at design-time