Search results for: acetabular defect

Authors: Samane Maroufi, Rasoul Khayyam Nekouei, Sajjad Sefimofarah, Veena Sahajwalla

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The present work details a three-stage strategy based on selective purification of rare earth oxide (REOs) isolated from end-of-life nickel-metal hydride (Ni-MH) batteries leading to high-yield fabrication of defect-rich Mn1-x-y(CeₓLaᵧ)O2-δ film. In step one, major impurities (Fe and Al) were removed from a REE-rich solution. In step two, the resulting solution with trace content of Mn was further purified through electrodeposition which resulted in the synthesis of a non-stoichiometric Mn₋₁₋ₓ₋ᵧ(CeₓLaₓᵧ)O2-δ ultra-thin film, with controllable thicknesses (5-650 nm) and transmittance (~29-100%)in which Ce4+/3+ and La3+ ions were dissolved in MnO2-x lattice. Due to percolation impacts on the optoelectronic properties of ultrathin films, a representative Mn1-x-y(CexLay)O2-δ film with 86% transmittance exhibited an outstanding areal capacitance of 3.4 mF•cm-2, mainly attributed to the intercalation/de-intercalation of anionic O2- charge carriers through the atomic tunnels of the stratified Mn1-x-y(CexLay)O2-δ crystallites. Furthermore, the Mn1-x-y(CexLay)O2-δ exhibited excellent capacitance retention of ~90% after 16,000 cycles. Such stability was shown to be associated with intervalence charge transfers occurring among interstitial Ce/La cations and Mn oxidation states within the Mn₋₁₋ₓ₋ᵧ(CexLay)O2-δ structure. The energy and power densities of the transparent flexible Mn₋₁₋ₓ₋ᵧ(CexLay)O2-δ full-cell pseudocapacitor device with a solid-state electrolyte was measured to be 0.088 µWh.cm-2 and 843 µW.cm-2, respectively. These values showed insignificant changes under vigorous twisting and bending to 45-180˚, confirming these materials are intriguing alternatives for size-sensitive energy storage devices. In step three, the remaining solution purified further, that led to the formation of REOs (La, Ce, and Nd) nanospheres with ~40-50 nm diameter.

Keywords: spent Ni-MH batteries, green energy, flexible pseudocapacitor, rare earth elements

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Authors: Muhammad Habib, Lin Tang, Guoliang Xue, Attaur Rahman, Myong-Ho Kim, Soonil Lee, Xuefan Zhou, Yan Zhang, Dou Zhang

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Designing a high-performance, lead-free ceramic has become a cutting-edge research topic due to growing concerns about the toxic nature of lead-based materials. In this work, a convenient strategy of compositional design and domain engineering is applied to the lead-fee BiFeO₃-BaTiO₃ ceramics, which provides a flexible polarization-free-energy profile for domain switching. Here, simultaneously enhanced dynamic piezoelectric constant (d33* = 772 pm/V) and a good thermal-stability (d33* = 26% over the temperature of 20-180 ᵒC) are achieved with a high Curie temperature (TC) of 432 ᵒC. This high piezoelectric strain performance is collectively attributed to multiple effects such as thermal quenching, suppression of defect charges by donor doping, chemically induced local structure heterogeneity, and electric field-induced phase transition. Furthermore, the addition of BT content decreased octahedral tilting, reduced anisotropy for domain switching and increased tetragonality (cₜ/aₜ), providing a wider polar length for B-site cation displacement, leading to high piezoelectric strain performance. Atomic-resolution transmission electron microscopy and piezoelectric force microscopy combined with X-ray diffraction results strongly support the origin of high piezoelectricity. The high and temperature-stable piezoelectric strain response of this work is superior to those of other lead-free ceramics. The synergistic approach of composition design and the concept present here for the origin of high strain response provides a paradigm for the development of materials for high-temperature piezoelectric actuator applications.

Keywords: Piezoelectric, BiFeO3-BaTiO3, Quenching, Temperature-insensitive

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Authors: Eng Toon Saw, Kun Liang Ang, Wei He, Xuecheng Dong, Seeram Ramakrishna

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Solvent recovery process is receiving utmost attention in recent year due to the scarcity of natural resource and consciousness of circular economy in chemical and pharmaceutical manufacturing process. Solvent dehydration process is one of the important process to recover and to purify the solvent for reuse. Due to the complexity of solvent waste or wastewater effluent produced in pharmaceutical industry resulting the wastewater treatment process become complicated, thus an alternative solution is to recover the valuable solvent in solvent waste. To treat solvent waste and to upgrade solvent purity, membrane pervaporation process is shown to be a promising technology due to the energy intensive and low footprint advantages. Ceramic membrane is adopted as solvent dehydration membrane owing to the chemical and thermal stability properties as compared to polymeric membrane. NaA zeolite membrane is generally used as solvent dehydration process because of its narrow and distinct pore size and high hydrophilicity. NaA zeolite membrane has been mainly applied in alcohol dehydration in fermentation process. At this stage, the membrane performance exhibits high separation factor with low flux using tubular ceramic membrane. Thus, defect free and ultrathin NaA membrane should be developed to increase water flux. Herein, we report a simple preparation protocol to prepare ultrathin NaA zeolite membrane supported on tubular ceramic membrane by controlling the seed size synthesis, seeding methods and conditions, ceramic substrate surface pore size selection and secondary growth conditions. The microstructure and morphology of NaA zeolite membrane will be examined and reported. Moreover, the membrane separation performance and stability will also be reported in isopropanol dehydration, ketone dehydration and ester dehydration particularly for the application in pharmaceutical industry.

Keywords: ceramic membrane, NaA zeolite, pharmaceutical industry, solvent recovery

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Authors: Anthony Oppong Kyekyeku, Sussana Antwi-Boasiako, Emmanuel De-Graft Johnson Owusu Ansah

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In this observational study, the performance of a known conventional storage system was tested and evaluated for fitness for its intended purpose. The system has a scope extended for the storage of dry cocoa beans. System sensitivity, reproducibility and uncertainties are not known in details. This study discusses the system performance in the context of existing literature on factors that influence the quality of cocoa beans during storage. Controlled conditions were defined precisely for the system to give reliable base line within specific established procedures. Minitab® 17 and R statistical software (R-3.3.1) were used for the statistical analyses. The approach to the storage system testing was to observe and compare through laboratory test methods the quality of the cocoa beans samples before and after storage. The samples were kept in Kilner jars and the temperature of the storage environment controlled and monitored over a period of 408 days. Standard test methods use in international trade of cocoa such as the cut test analysis, moisture determination with Aqua boy KAM III model and bean count determination were used for quality assessment. The data analysis assumed the entire population as a sample in order to establish a reliable baseline to the data collected. The study concluded a statistically significant mean value at 95% Confidence Interval (CI) for the performance data analysed before and after storage for all variables observed. Correlational graphs showed a strong positive correlation for all variables investigated with the exception of All Other Defect (AOD). The weak relationship between the before and after data for AOD had an explained variability of 51.8% with the unexplained variability attributable to the uncontrolled condition of hidden infestation before storage. The current study concluded with a high-performance criterion for the storage system.

Keywords: benchmarking performance data, cocoa beans, hidden infestation, storage system validation

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Authors: Eunice Chiamaka Allen-Ngbale

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Prior to bill of lading (BOL), merchants travelled along with their goods; then recorded the goods in the ship’s mates’ register; and finally started selling the goods while in transit by way of BOL, indicative that BOL is negotiable. Common law doctrine of privity of contract did not allow the transfer of right to sue to a non-party to the contract. This created hardship to cargo owners, which made many jurisdictions enact laws in this regard. Bill of Lading Act 1855 (BLA) was enacted in the United Kingdom, which applied as statute of general application under section 375 Merchant Shipping Act 1990 (MSA) in Nigeria; and conferred contractual rights of the suit on consignees and endorsees, but on the passing of ownership upon or by reason of such consignment or endorsement on the shipment of the goods simultaneously. The repeal of section 375 MSA by section 439 MSA 2007 created a lacuna, and the doctrine of privity of contract is the extant law in Nigeria. The aim of this study is to evaluate laws governing the transfer of the contractual right of suit to a third party under the bill of lading in Nigeria. The specific objectives of this study are to ascertain: (i) whether the extant law of common law doctrine of privity of the contract covers the transfer of the right of suit to the third party under the bill of lading in Nigeria; (ii) impediment(s) of the common law to transfer such right in Nigeria in the absence of any legislation; (iii) the level of applicability of the doctrine of privity of contract as it relates to transfer of the contractual right of suit to third party under the bill of lading in Nigeria; and (iv) whether to proffer possible suggestion on how to fill the lacuna left by the repeal of Merchant Shipping Act 1990. This work adopted a doctrinal approach with reliance on primary and secondary source materials. It finds that the common law doctrine of privity of contract in Nigeria is retrogressive. This work recommends for amendment of the relevant statute to cure this defect/lacuna like other commonwealth nations for best international practices.

Keywords: contract of carriage by sea, doctrine of privity of contract, lawful holder of bill of lading, third party right of suit

Procedia PDF Downloads 134

Authors: Samane Maroufi, Rasoul Khayyam Nekouei, Sajjad Mofarah

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Fabrication of the state-of-the-art portable pseudocapacitors with the desired transparency, mechanical flexibility, capacitance, and durability is challenging. In most cases, the fabrication of such devices requires critical elements which are either under the crisis of depletion or their extraction from virgin mineral ores have sever environmental impacts. This urges the use of secondary resources instead of virgin resources in fabrication of advanced devices. In this research, ultrathin films of defect-rich Mn1−x−y(CexLay)O2−δ with controllable thicknesses in the range between 5 nm to 627 nm and transmittance (≈29–100%) have been fabricated via an electrochemical chronoamperometric deposition technique using an aqueous precursor derived during the selective purification of rare earth oxide (REOs) isolated from end-of-life nickel-metal hydride (Ni-MH) batteries. Intercalation/de-intercalation of anionic O2− through the atomic tunnels of the stratified Mn1−x−y(CexLay)O2−δ crystallites was found to be responsible for outstanding areal capacitance of 3.4 mF cm−2 of films with 86% transmittance. The intervalence charge transfer among interstitial Ce/La cations and Mn oxidation states within the Mn1−x−y(CexLay)O2−δ structure resulted in excellent capacitance retention of ≈90% after 16 000 cycles. The synthesised transparent flexible Mn1−x−y(CexLay)O2−δ full-cell pseudocapacitor device possessed the energy and power densities of 0.088 μWh cm⁻² and 843 µW cm⁻², respectively. These values show insignificant changes under vigorous twisting and bending to 45–180° confirming these value-added materials are intriguing alternatives for size-sensitive energy storage devices. This research confirms the feasibility of utilisation of secondary waste resources for the fabrication of high-quality pseudocapacitors with engineered defects with the desired flexibility, transparency, and cycling stability suitable for size-sensitive portable electronic devices.

Keywords: pseudocapacitors, energy storage devices, flexible and transparent, sustainability

Procedia PDF Downloads 55

Authors: Ilja Käch, Abdul R. Jandali, Nadja Zechmann-Müller

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Introduction: We discuss the treatment of two young male patients suffering from scaphoid non-union after a traumatic scaphoid fracture. The currently propagated techniques for treating a scaphoid non-union in children are either the operative reconstruction of the scaphoid or the conservative treatment with splinting in a scaphoid cast. Cases: In the first case, we operated on a 13 years old male patient with a posttraumatic scaphoid non-union in the middle third with a humpback deformity. We resected the middle third of the scaphoid and grafted the defect with an iliac crest bone, and the DISI-Deformity was reduced. Fixation was performed with K-Wires and immobilisation in a scaphoid cast. In the second case a 13 years old male patient also with a posttraumatic scaphoid non-union in the middle third and humpback deformity, DISI-deformity, was treated conservatively. Immobilisation in a scaphoid cast for four months was performed. Results: Operative: One year postoperatively the patient achieved a painless free arc of motion. Flexion/Extension 70/0/60°, Radial-/Ulnarduction 30/0/30° and Pro-/Supination 90/0/90°. The computer tomogram showed complete consolidation and bony fusion of the iliac crest bone. Conservative: Six to eight months after conservative treatment the patient demonstrated painless motion and AROM Flexion/Extension 80/0/80°, Radial-/Ulnarduction and Pro-/Supination in maximum range. Complete consolidation in the computer tomogram with persistent humpback- and DISI deformity. Conclusion: In the literature, both techniques are described, either the operative scaphoid reconstruction or the conservative treatment with splinting. In our cases, both the operative and conservative treatments showed comparable good results. However, the humpback- and DISI deformity can only be addressed with a surgical approach.

Keywords: scaphoid, non-union, trauma, operative vs. non operative

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Authors: Silpita Paul, Susanta Sadhukhan, Biswanath Maity, Madhusudan Das

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Neural tube defects (NTDs) are one of the most common forms of birth defect and affect ~300,000 new born worldwide each year. The prevalence is higher in Northern India (11 per 1000 birth) compare to southern India (5 per 1000 birth). NTDs are one of the common birth defects related with low blood folate and Hcy concentration. Though the mechanism is still unknown, but it is now established that, NTDs in human are polygenic in nature and follow the heterogeneous trait. In spite of its heterogeneity, polymorphism in few genes affects significantly the trait of NTDs. Polymorphisms in the genes FOLH1 and MTHFR plays important role in NTDs. In this study, the polymorphisms of these genes were screened by bi-directional sequencing from 30 mothers with NTD babies as case. The result revealed that 26.67% patients had bi-allelic FOLH1 polymorphism. The polymorphism has been identified as p.Y60H and frequent to cause NTDs. The study of MTHFR gene showed 2 different SNPs rs1801131 (at exon 4) and rs1801131 (at exon 7). The study showed 6.67% patients of both mono- and bi-allelic MTHFR-rs1801131 polymorphism and 6.67% patients of bi-allelic MTHFR-rs1801131 polymorphism. These polymorphisms has been responsible for p.A222V and p.E429A change respectively and frequently involved in NTD formation. Those polymorphisms affect mainly the absorption of dietary folate from intestine and the formation of 5-methylenetetrahydrofolate (5 MTHF) from 5,10-methylenetetrahydrofolate (5,10- MTHF), which is the functional folate form in our system. Though the study is not complete yet, but these polymorphisms play crucial roles in the formation of NTDs in other world population. Based on the result till date, it can be concluded that they also play significant role in our population too as in control samples we have not found any changes.

Keywords: neural tube defects, polymorphism, FOLH1, MTHFR

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Authors: W. Thepsuwan, N. Monmaturapoj

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Calcium phosphate cements (CPCs) is one of the most attractive bioceramics due to its moldable and shape ability to fill complicated bony cavities or small dental defect positions. In this study, CPCs were produced by using mixtures of tetracalcium phosphate (TTCP, Ca4O(PO4)2) and dicalcium phosphate anhydrous (DCPA, CaHPO4) in equimolar ratio (1/1) with aqueous solutions of acetic acid (C2H4O2) and disodium hydrogen phosphate dehydrate (Na2HPO4.2H2O) in combination with sodium alginate in order to improve theirs moldable characteristic. The concentrations of the aqueous solutions and sodium alginate were varied to investigate the effects of different aqueous solution and alginate on properties of the cements. The cement paste was prepared by mixing cement powder (P) with aqueous solution (L) in a P/L ratio of 1.0 g/ 0.35 ml. X-ray diffraction (XRD) was used to analyses phase formation of the cements. Setting times and compressive strength of the set CPCs were measured using the Gilmore apparatus and Universal testing machine, respectively. The results showed that CPCs could be produced by using both basic (Na2HPO4.2H2O) and acidic (C2H4O2) solutions. XRD results show the precipitation of hydroxyapatite in all cement samples. No change in phase formation among cements using difference concentrations of Na2HPO4.2H2O solutions. With increasing concentration of acidic solutions, samples obtained less hydroxyapatite with a high dicalcium phosphate dehydrate leaded to a shorter setting time. Samples with sodium alginate exhibited higher crystallization of hydroxyapatite than that of without alginate as a result of shorten setting time in basic solution but a longer setting time in acidic solution. The stronger cement was attained from samples using acidic solution with sodium alginate; however it was lower than using the basic solution.

Keywords: calcium phosphate cements, TTCP, DCPA, hydroxyapatite, properties

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Authors: Marta Kozuń, Krystian Toczewski, Sylwester Gerus, Justyna Wolicka, Kamila Boberek, Jarosław Filipiak, Dariusz Patkowski

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Long gap esophageal atresia is a congenital defect and is a challenge for pediatric surgeons all over the world. There are different surgical techniques in use to treat atresia. One of them is esophageal elongation but the optimal suture placement technique to achieve maximum elongation with low-risk complications is still unknown. The aim of the study was to characterize the process of esophageal elongation from the biomechanical point of view. Esophagi of white Pekin Duck was used as a model based on the size of this animal which is similar to a newborn (2.5-4kg). The specimens were divided into two groups: the control group (CG) and the group with sutures (SG). The esophagi of the control group were mounted in the grips of the MTS Tytron 250 testing machine and tensile test until rupture was performed. The loading speed during the test was 10mm/min. Then the SG group was tested. Each esophagus was cut into two equal parts and that were fused together using surgical sutures. The distance between both esophagus parts was 20mm. Ten both ends were mounted on the same testing machine and the tensile test with the same parameters was conducted. For all specimens, force and elongation were recorded. The biomechanical properties, i.e., the maximal force and maximal elongation, were determined on the basis of force-elongation curves. The maximal elongation was determined at the point of maximal force. The force achieved with the suture group was 10.1N±1.9N and 50.3N±11.6N for the control group. The highest elongation was also obtained for the control group: 18mm±3mm vs. 13.5mm ±2.4mm for the suture group. The presented study expands the knowledge of elongation of esophagi. It is worth emphasizing that the duck esophagus differs from the esophagus of a newborn, i.e., its wall lacks striated muscle cells. This is why the parts of animal esophagi used in the research are may characterized by different biomechanical properties in comparison with newborn tissue.

Keywords: long gap atresia treatment, esophageal elongation, biomechanical properties, soft tissue

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Authors: Vaibhav Pandey, K. Chattopadhyay, N. C. Santhi Srinivas, Vakil Singh

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Aluminium alloy 7075 consist of different intermetallic precipitate particles MgZn2, CuAl2, which result in heterogeneity of micro structure and influence the corrosion properties of the alloy. Artificial ageing was found to enhance the strength properties, but highly susceptible to stress-corrosion cracking. Various conventional surface modification techniques are developed for improving corrosion properties of aluminum alloys. This led to development of novel surface mechanical attrition treatment (SMAT) technique the so called ultrasonic shot peening which gives nano-grain structure at surface. In the present investigation the influence of surface mechanical attrition treatment on corrosion behavior of aluminum alloy 7075 was studied in 3.5wt% NaCl solution. Two different size of 1 mm and 3 mm steel balls are used as peening media and SMAT was carried out for different time intervals 5, 15 and 30 minutes. Surface nano-grains/nano-crystallization was observed after SMAT. The formation of nano-grain structure was observed for larger size balls with time of treatment and consequent increase in micro strain. As-SMATed sample with 1 mm balls exhibits better corrosion resistance as compared to that of un-SMATed sample. The enhancement in corrosion resistance may be due to formation of surface nano-grain structure which reduced the electron release rate. In contrast the samples treated with 3 mm balls showed very poor corrosion resistance. A decrease in corrosion resistance was observed with increase in the time of peening. The decrease in corrosion resistance in the shotpeened samples with larger diameter balls may due to increase in microstrain and defect density.

Keywords: aluminum alloy 7075, corrosion, SMAT, ultrasonic shot peening, surface nano-grains

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Authors: Hamidullah Binol, Abdullah Bal

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Nowadays, food safety is a great public concern; therefore, robust and effective techniques are required for detecting the safety situation of goods. Hyperspectral Imaging (HSI) is an attractive material for researchers to inspect food quality and safety estimation such as meat quality assessment, automated poultry carcass inspection, quality evaluation of fish, bruise detection of apples, quality analysis and grading of citrus fruits, bruise detection of strawberry, visualization of sugar distribution of melons, measuring ripening of tomatoes, defect detection of pickling cucumber, and classification of wheat kernels. HSI can be used to concurrently collect large amounts of spatial and spectral data on the objects being observed. This technique yields with exceptional detection skills, which otherwise cannot be achieved with either imaging or spectroscopy alone. This paper presents a nonlinear technique based on kernel Fukunaga-Koontz transform (KFKT) for detection of fat content in ground meat using HSI. The KFKT which is the nonlinear version of FKT is one of the most effective techniques for solving problems involving two-pattern nature. The conventional FKT method has been improved with kernel machines for increasing the nonlinear discrimination ability and capturing higher order of statistics of data. The proposed approach in this paper aims to segment the fat content of the ground meat by regarding the fat as target class which is tried to be separated from the remaining classes (as clutter). We have applied the KFKT on visible and nearinfrared (VNIR) hyperspectral images of ground meat to determine fat percentage. The experimental studies indicate that the proposed technique produces high detection performance for fat ratio in ground meat.

Keywords: food (ground meat) inspection, Fukunaga-Koontz transform, hyperspectral imaging, kernel methods

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Authors: S. AliReza Mirghasemi, Zameer Hussain, Mohammad Saleh Sadeghi, Narges Rahimi Gabaran, Mohamadreza Baghaban Eslaminejad

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Background: Despite promising results have shown by osteogenic cell-based demineralized bone matrix composites, they need to be optimized for grafts that act as structural frameworks in load-bearing defects. The purpose of this experiment is to determine the effect of bone-marrow-mesenchymal-stem-cells seeding on partially demineralized laser-perforated structural allografts that have been implanted in critical femoral defects. Materials and Methods: P3 stem cells were used for graft seeding. Laser perforation in four rows of three holes was achieved. Cell-seeded grafts were incubated for one hour until they were planted into the defect. We used four types of grafts: partially demineralized only (Donly), partially demineralized stem cell seeded (DST), partially demineralized laser-perforated (DLP), and partially demineralized laser-perforated stem cell seeded (DLPST). histologic and histomorphometric analysis were performed at 12 weeks. Results: Partially demineralized laser-perforated had the highest woven bone formation within graft limits, stem cell seeded demineralized laser-perforated remained intact, and the difference between partially demineralized only and partially demineralized stem cell seeded was insignificant. At interface, partially demineralized laser-perforated and partially demineralized only had comparable osteogenesis, but partially demineralized stem cell seeded was inferior. The interface in stem cell seeded demineralized laser-perforated was almost replaced by distinct endochondral osteogenesis with higher angiogenesis in the vicinity. Partially demineralized stem cell seeded and stem cell seeded demineralized laser-perforated graft surfaces had extra vessel-ingrowth-like porosities, a sign of delayed resorption. Conclusion: This demonstrates that simple cell-based composites are not optimal and necessitates the supplementation of synergistic stipulations and surface changes.

Keywords: structural bone allograft, partial demineralization, laser perforation, mesenchymal stem cell

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Authors: Seyedeh Mozhgan Seyed Talebi, Chih -Hao Lee

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With an abrupt rise in the power conservation efficiency (PCE) of perovskite solar cells (PSCs) within a short span of time, the toxicity of lead was raised as a major hurdle in the path toward their commercialization. In the present research, a systematic investigation of the electrical and optical characteristics of the all-inorganic CsSnI₃ perovskite absorber layer was performed with the Vienna Ab Initio Simulation Package (VASP) using the projector-augmented wave method. The presence of inorganic halide perovskite offers the advantages of enhancing the degradation resistance of the device, reducing the cost of cells, and minimizing the recombination of generated carriers. The simulated standard device using a 1D simulator like solar cell capacitance simulator (SCAPS) version 3308 involves FTO/n-TiO₂/CsSnI₃ Perovskite absorber/Spiro OmeTAD HTL/Au contact layer. The variation in the device design key parameters such as the thickness and defect density of perovskite absorber, hole transport layer and electron transport layer and interfacial defects are examined with their impact on the photovoltaic characteristic parameters. The effect of an increase in operating temperature from 300 K to 400 K on the performance of CsSnI3-based perovskite devices is also investigated. The optimized standard device at room temperature shows the highest PCE of 25.18 % with FF of 75.71 %, Voc of 0.96 V, and Jsc of 34.67 mA/cm². The outcomes and interpretation of different inorganic Cu-based HTLs presence, such as CuSCN, Cu₂O, CuO, CuI, SrCu₂O₂, and CuSbS₂, here represent a critical avenue for the possibility of fabricating high PCE perovskite devices made of stable, low-cost, efficient, safe, and eco-friendly all-inorganic materials like CsSnI₃ perovskite light absorber.

Keywords: CsSnI₃, hole transporting layer (HTL), lead-free perovskite solar cell, SCAPS-1D software

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Authors: Jae-Il Jeong, Hoon-Jae Park, Jung-Woo Cho, Yang-Gon Kim, Jin-Young Park, Joo-Young Oh, Si-Geun Choi, Seock-Sam Kim, Young Tae Cho, Chan Gyu Kim, Jong-Hyoung Kim

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Bearing component has strongly required to decrease vibration and wear to achieve high durability and life time. In the industry field, bearing durability is improved by surface treatment on the bearing surface by centrifugal casting or gravity casting production method. However, this manufacturing method has caused problems such as long processing time, defect rate, and health harmful effect. To solve this problem, there is a laser cladding deposition treatment, which provides fast processing and food adhesion. Therefore, optimum conditions of white metal laser deposition should be studied to minimize bearing contact axis wear using laser cladding techniques. In this study, we deposit a soft white metal layer on SCM440, which is mainly used for shaft and bolt. On laser deposition process, the laser power and powder feed rate and laser head speed factors are controlled to find out the optimal conditions. We also measure hardness using micro Vickers, analyze FE-SEM (Field Emission Scanning Electron Microscope) and EDS (Energy Dispersive Spectroscopy) to study the mechanical properties and surface characteristics with various parameters change. Furthermore, this paper suggests the optimum condition of laser cladding deposition to apply in industrial fields. This work was supported by the Industrial Innovation Project of the Korea Evaluation Institute of Industrial Technology (KEIT) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (Research no. 10051653).

Keywords: laser deposition, bearing, white metal, mechanical properties

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Authors: Hardisiswo Soedjana, Inne Caroline

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Deep dermal or full thickness burns are inevitably lead to post-burn contractures. These contractures remain to be one of the most concerning late complications of burn injuries. Surgical management includes releasing the contracture followed by resurfacing the defect accompanied by post-operative rehabilitation. Optimal treatment of post-burn contractures depends on the characteristics of the contractures. This study is aimed to describe clinical characteristics, problems, and management of post-burn contractures in adults and children. A retrospective analysis was conducted from medical records of patients suffered from contractures after burn injuries admitted to Hasan Sadikin general hospital between January 2016 and January 2018. A total of 50 patients with post burn contractures were included in the study. There were 17 adults and 33 children. Most patients were male, whose age range within 15-59 years old and 5-9 years old. Educational background was mostly senior high school among adults, while there was only one third of children who have entered school. Etiology of burns was predominantly flame in adults (82.3%); whereas flame and scald were the leading cause of burn injury in children (11%). Based on anatomical regions, hands were the most common affected both in adults (35.2%) and children (48.5%). Contractures were identified in 6-12 months since the initial burns. Most post-burn hand contractures were resurfaced with full-thickness skin graft (FTSG) both in adults and children. There were 11 patients who presented with recurrent contracture after previous history of contracture release. Post-operative rehabilitation was conducted for all patients; however, it is important to highlight that it is still challenging to control splinting and exercise when patients are discharged and especially the compliance in children. In order to improve quality of life in patients with history of deep burn injuries, prevention of contractures should begin right after acute care has been established. Education for the importance of splinting and exercise should be administered as comprehensible as possible for adult patients and parents of pediatric patients.

Keywords: burn, contracture, education, exercise, splinting

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Authors: Kwan-Ho Kim, Jin-Hong Park

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The multi-valued logic (MVL) circuits, which can handle more than two logic states, are one of the promising solutions to overcome the bit density limitations of conventional binary logic systems. Recently, tunneling devices such as Esaki diode and resonant tunneling diode (RTD) have been extensively explored to construct the MVL circuits. These tunneling devices present a negative differential resistance (NDR) phenomenon in which a current decreases as a voltage increases in a specific applied voltage region. Due to this non-monotonic current behavior, the tunneling devices have more than two threshold voltages, consequently enabling construction of MVL circuits. Recently, the emergence of two dimensional (2D) van der Waals (vdW) crystals has opened up the possibility to fabricate such tunneling devices easily. Owing to the defect-free surface of the 2D crystals, a very abrupt junction interface could be formed through a simple stacking process, which subsequently allowed the implementation of a high-performance tunneling device. Here, we report a vdW heterostructure based tunneling device with multiple threshold voltages, which was fabricated with black phosphorus (BP) and hafnium diselenide (HfSe₂). First, we exfoliated BP on the SiO₂ substrate and then transferred HfSe₂ on BP using dry transfer method. The BP and HfSe₂ form type-Ⅲ heterojunction so that the highly doped n+/p+ interface can be easily implemented without additional electrical or chemical doping process. Owing to high natural doping at the junction, record high peak to valley ratio (PVCR) of 16 was observed to the best our knowledge in 2D materials based NDR device. Furthermore, based on this, we first demonstrate the feasibility of the ternary latch by connecting two multi-threshold voltage devices in series.

Keywords: two dimensional van der Waals crystal, multi-valued logic, negative differential resistnace, tunneling device

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Authors: Emmanuel Kamal Aziz Saba, Gihan Abd El-Lateif Younis El-Tantawi, Mohammed Hamdy Zahran, Ibrahim Khalil Ibrahim, Mohammed Abd El-Salam Shehata, Hussein Al-Moghazy Sultan, Medhat

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Pelvic floor electrophysiological tests are essential for assessment of patients with obstructed defecation. The present study was conducted to determine the different patterns of pelvic floor electrophysiology that are associated with obstructed defecation. The present cross sectional study included 25 patients with obstructed defecation. A control group of 20 apparently healthy subjects were included. All patients were subjected to history taking, clinical examination, proctosigmoidoscopy, lateral proctography (evacuation proctography), dynamic pelvic magnetic resonance imaging, anal manometry and electrophysiological studies. Electrophysiological studies were including pudendal nerve motor conduction study, pudendo-anal reflex, needle electromyography of external anal sphincter and puborectalis muscles, pudendal somatosensory evoked potential and tibial somatosensory evoked potential. The control group was subjected to electrophysiological studies which included pudendal nerve motor conduction study, pudendo-anal reflex, pudendal somatosensory evoked potential and tibial somatosensory evoked potential. The most common pelvic floor electrodiagnostic pattern characteristics of obstructed defecation was pudendal neuropathy, denervation and anismus of external anal sphincter and puborectalis with complete interference pattern of external anal sphincter and puborectalis at squeezing and cough and no localized defect in external anal sphincter. In conclusion, there were characteristic pelvic floor electrodiagnostic patterns associated with obstructed defecation.

Keywords: obstructed defecation, pudendal nerve terminal motor latency, pudendoanal reflex, sphincter electromyography

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Authors: Afzaal Bashir, Sunaina Afzaal

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Background: Facial contour deformities associated with pigmentary changes are of major concern for plastic surgeons, both being important and difficult in treating such issues. No definite ideal treatment option is available to simultaneously address both the contour defect as well as related pigmentation. Objectives: The aim of the current study is to compare the long-term effects of conventional adipose tissue grafting and ex-vivo expanded Mesenchymal Stem Cells enriched adipose tissue grafting for the treatment of contour deformities with pigmentary changes on the face. Material and Methods: In this study, eighty (80) patients with contour deformities of the face with hyperpigmentation were recruited after informed consent. Two techniques i.e., conventional fat grafting (C-FG) and fat grafts enriched with expanded adipose stem cells (FG-ASCs), were used to address the pigmentation. Both techniques were explained to patients, and enrolled patients were divided into two groups i.e., C-FG and FG-ASCS, per patients’ choice and satisfaction. Patients of the FG-ASCs group were treated with fat grafts enriched with expanded adipose stem cells, while patients of the C-FGs group were treated with conventional fat grafting. Patients were followed for 12 months, and improvement in face pigmentation was assessed clinically as well as measured objectively. Patient satisfaction was also documented as highly satisfied, satisfied, and unsatisfied. Results: Mean age of patients was 24.42(±4.49), and 66 patients were females. The forehead was involved in 61.20% of cases, the cheek in 21.20% of cases, the chin in 11.20% of cases, and the nose in 6.20% of cases. In the GF-ASCs group, the integrated color density (ICD) was decreased (1.08×10⁶ ±4.64×10⁵) as compared to the C-FG group (2.80×10⁵±1.69×10⁵). Patients treated with fat grafts enriched with expanded adipose stem cells were significantly more satisfied as compared to patients treated with conventional fat grafting only. Conclusion: Mesenchymal stem cell-enriched autologous fat grafting is a preferred option for improving the contour deformities related to increased pigmentation of face skin.

Keywords: hyperpigmentation, color density, enriched adipose tissue graft, fat grafting, contour deformities, Image J

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Authors: Dina Athariah, Desriani Desriani, Bugi Ratno Budiarto, Abinawanto Abinawanto, Dwi Wulandari

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Breast cancer is a regulated by many genes. Defect in PIK3CA gene especially at position of exon 9 (E542K and E545K), called hot spot mutation induce early transformation of breast cells. The early detection of breast cancer based on mutation profile of this hot spot region would be hampered by the existence of pseudogene, marked by its substitution mutation at base 1658 (E545A) and deletion at 1659 that have been previously proven in several cancers. To the best of the authors’ knowledge, until recently no studies have been reported about pseudogene phenomenon in breast cancer. Here, we reported PCR optimization to to obtain true exon 9 of PIK3CA gene from its pseudogene hence increasing the validity of data. Material and methods: two genomic DNA with Dev and En code were used in this experiment. Two pairs of primer were design for Standard PCR method. The size of PCR products for each primer is 200bp and 400bp. While other primer was designed for Nested-PCR followed with DNA sequencing method. For Nested-PCR, we optimized the annealing temperature in first and second run of PCR, and the PCR cycle for first run PCR (15x versus 25x). Result: standard PCR using both primer pairs designed is failed to detect the true PIK3CA gene, appearing a substitution mutation at 1658 and deletion at 1659 of PCR product in sequence chromatogram indicated pseudogene. Meanwhile, Nested-PCR with optimum condition (annealing temperature for the first round at 55oC, annealing temperatung for the second round at 60,7oC with 15x PCR cycles) and could detect the true PIK3CA gene. Dev sample were identified as WT while En sample contain one substitution mutation at position 545 of exon 9, indicating amino acid changing from E to K. For the conclusion, pseudogene also exists in breast cancer and the apllication of optimazed Nested-PCR in this study could detect the true exon 9 of PIK3CA gene.

Keywords: breast cancer, exon 9, hotspot mutation, PIK3CA, pseudogene

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Authors: Mahmoud A. Amin, Essam Taman, Ahmed Omran, Mahmoud Shawky, Ahmed Mekawy, Abdallah M. Kotkat, Saber Younes, Nehad N. Ghonemy, Amin Saad, Ezz-Aleslam, Abdullah M. Elosh

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Introduction: TMJ is a one-of-a-kind, complicated synovial joint that helps with masticatory function by allowing the mandible to open and close the mouth. True ankylosis is a situation in which condylar movement is limited by a mechanical defect in the joint, whereas false ankylosis is a condition in which there is a restriction in mandibular movement due to muscular spasm myositis ossificans, and coronoid process hyperplasia. Ankylosis is characterized by the inability to open the mouth due to fusion of the TMJ condyle to the base of the skull as a result of trauma, infection, or systemic diseases such as rheumatoid arthritis (the most common) and psoraisis. Ankylosis causes facial asymmetry and affects the patient psychologically as well as speech, difficult mastication, poor oral hygiene, malocclusion, and other factors. TMJ is a technically challenging joint; hence TMJ ankylosis management is complicated. Case presentation: this case is a male patient 25 years old reported to our maxillofacial clinic in Damietta faculty of medicine, Al-Azhar University with the inability to open the mouth at all, with a history of difficulty of mouth breathing and eating foods, there was a history of falling from height at 2006, and the patient underwent corrective surgery before with no improvement because the ankylosis was relapsed short period after the previous operations with that done out of our hospital inter-incisor distant ZERO so, this condition need mandatory management. Clinical examination and radiological investigations were done after complete approval from the patient and his brother; tracheostomy was done for our patient before the operation. The patient entered the operation in our hospital and drastic improvement in mouth opening was noticed, helping to restore the physical psychological health of the patient.

Keywords: temporomandibular joint, TMJ, Ankylosis, mouth opening, physiotherapy, condylar plate

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Authors: P. Caimmi, E. Bele, A. Abolfathi

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Lattice materials are cellular structures composed of a periodic network of beams. They offer high weight-specific mechanical properties and lend themselves to numerous weight-sensitive applications. The periodic internal structure responds to external vibrations through characteristic frequency bandgaps, making these materials suitable for the reduction of noise and vibration. However, the deviation from architectural homogeneity, due to, e.g., manufacturing imperfections, has a strong influence on the mechanical properties and vibration response of these materials. In this work, we present results on the influence of geometric imperfections on the vibration response of hexagonal lattices. Three classes of geometrical variables are used: the characteristics of the architecture (relative density, ligament length/cell size ratio), imperfection type (degree of non-periodicity, cracks, hard inclusions) and defect morphology (size, distribution). Test specimens with controlled size and distribution of imperfections are manufactured through selective laser sintering. The Frequency Response Functions (FRFs) in the form of accelerance are measured, and the modal shapes are captured through a high-speed camera. The finite element method is used to provide insights on the extension of these results to semi-infinite lattices. An updating procedure is conducted to increase the reliability of numerical simulation results compared to experimental measurements. This is achieved by updating the boundary conditions and material stiffness. Variations in FRFs of periodic structures due to changes in the relative density of the constituent unit cell are analysed. The effects of geometric imperfections on the dynamic response of periodic structures are investigated. The findings can be used to open up the opportunity for tailoring these lattice materials to achieve optimal amplitude attenuations at specific frequency ranges.

Keywords: lattice architectures, geometric imperfections, vibration attenuation, experimental modal analysis

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Authors: Kathryn L. Duncan, Charles A. Kuntz, James O. Simcock

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A surgical approach to the cranium for treatment of frontal lobe and olfactory bulb neoplasia in dogs is described in this report, which provided excellent access for visualisation and removal of gross neoplastic tissue. An 8-year-old spayed female Shih Tzu crossbreed dog (dog 1) and a 13-year-old neutered male Miniature Fox Terrier (dog 2) were evaluated for removal of neoplasms involving both the frontal lobe and olfactory bulb. Both dogs presented with abnormal neurological clinical signs, decreased menace responses, and behavioural changes. Additionally, dog 2 presented with compulsive circling and generalized tonic-clonic seizure activity. Computed tomography was performed in both dogs, and MRI was also performed in dog 1. Imaging was consistent with frontal lobe and olfactory bulb neoplasia. A transorbital frontal bone craniectomy, with orbital ligament desmotomy and ventrolateral retraction of the globe, was performed in both cases without complication. Dog 1 had a focal area of lysis in the frontal bone adjacent to the neoplasm in the frontal lobe. The presence of the bone defect provided part of the impetus for this approach, as it would permit resection of the lytic bone. In addition, the neoplasms would be surgically accessible without encountering interposed brain parenchyma, reducing the risk of iatrogenic injury. Both dogs were discharged from the hospital within 72 hours post-operatively, both with normal mentation. Case 1 had a histopathologic diagnosis of malignant anaplastic neoplasm. The tumour recurred 101d postoperatively, and the patient was euthanized. Case 2 was diagnosed with a meningioma and was neurologically normal at 294d postoperatively. This transorbital surgical approach allowed successful removal of the intracranial frontal lobe and olfactory bulb neoplasms in 2 dogs. This approach should be considered for dogs with lateralized frontal lobe and olfactory bulb neoplasms that are closely associated with the suborbital region of the frontal bone.

Keywords: neurosurgery, small animal surgery, surgical oncology, veterinary neurology

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Authors: Ayoade Adeyemi, Leo Nherera, Paul Trueman, Antje Emmermann

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Background and objectives: Radiofrequency (RF) generated plasma chondroplasty is considered a promising treatment alternative to mechanical debridement (MD) with a shaver. The aim of the study was to perform a cost-effectiveness analysis comparing costs and outcomes following COBLATION chondroplasty versus mechanical debridement in patients with knee pain associated with a medial meniscus tear and idiopathic ICRS grade III focal lesion of the medial femoral condyle from a payer perspective. Methods: A decision-analytic model was developed comparing economic and clinical outcomes between the two treatment options in German patients following knee chondroplasty. Revision rates based on the frequency of repeat arthroscopy, osteotomy and conversion to total knee replacement, reimbursement costs and outcomes data over a 4-year time horizon were extracted from published literature. One-way sensitivity analyses were conducted to assess uncertainties around model parameters. Threshold analysis determined the revision rate at which model results change. All costs were reported in 2016 euros, future costs were discounted at a 3% annual rate. Results: Over a 4 year period, COBLATION chondroplasty resulted in an overall net saving cost of €461 due to a lower revision rate of 14% compared to 48% with MD. Threshold analysis showed that both options were associated with comparable costs if COBLATION revision rate was assumed to increase up to 23%. The initial procedure costs for COBLATION were higher compared to MD and outcome scores were significantly improved at 1 and 4 years post-operation versus MD. Conclusion: The analysis shows that COBLATION chondroplasty is a cost-effective option compared to mechanical debridement in the treatment of patients with a medial meniscus tear and idiopathic ICRS grade III defect of the medial femoral condyle.

Keywords: COBLATION, cost-effectiveness, knee chondroplasty, mechanical debridement

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Authors: Michael Shandalov, Tzvi Templeman, Michael Schmidt, Itzhak Kelson, Eyal Yahel

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We present a new method to produce a model system for the study of radiation damage in non-radioactive materials. The method is based on homogeneously incorporating 228Th ions in PbS thin films using a small volume chemical bath deposition (CBD) technique. The common way to alloy metals with radioactive elements is by melting pure elements, which requires considerable amounts of radioactive material with its safety consequences such as high sample activity. Controlled doping of the thin films with (very) small amounts (100-200ppm) of radioactive elements such as thorium is expected to provide a unique path for studying radiation damage in materials due to decay processes without the need of sealed enclosure. As a first stage, we developed CBD process for controlled doping of PbS thin films (~100 nm thick) with the stable isotope (t1/2~106 years), 232Th. Next, we developed CBD process for controlled doping of PbS thin films with active 228Th isotope. This was achieved by altering deposition parameters such as temperature, pH, reagent concentrations and time. The 228Th-doped films were characterized using X-ray diffraction, which indicated a single phase material. Film morphology and thickness were determined using scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) mapping in the analytical transmission electron microscope (A-TEM), X-ray photoelectron spectroscopy (XPS) depth profiles and autoradiography indicated that the Th ions were homogeneously distributed throughout the films, suggesting Pb substitution by Th ions in the crystal lattice. The properties of the PbS (228Th) film activity were investigated by using alpha-spectroscopy and gamma spectroscopy. The resulting films are applicable for isochronal annealing of resistivity measurements and currently under investigation. This work shows promise as a model system for the analysis of dilute defect systems in semiconductor thin films.

Keywords: thin films, doping, radiation damage, chemical bath deposition

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Authors: Hira Lal Gope, Hidekazu Fukai

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The aim of this study is to develop a system which can identify and sort peaberries automatically at low cost for coffee producers in developing countries. In this paper, the focus is on the classification of peaberries and normal coffee beans using image processing and machine learning techniques. The peaberry is not bad and not a normal bean. The peaberry is born in an only single seed, relatively round seed from a coffee cherry instead of the usual flat-sided pair of beans. It has another value and flavor. To make the taste of the coffee better, it is necessary to separate the peaberry and normal bean before green coffee beans roasting. Otherwise, the taste of total beans will be mixed, and it will be bad. In roaster procedure time, all the beans shape, size, and weight must be unique; otherwise, the larger bean will take more time for roasting inside. The peaberry has a different size and different shape even though they have the same weight as normal beans. The peaberry roasts slower than other normal beans. Therefore, neither technique provides a good option to select the peaberries. Defect beans, e.g., sour, broken, black, and fade bean, are easy to check and pick up manually by hand. On the other hand, the peaberry pick up is very difficult even for trained specialists because the shape and color of the peaberry are similar to normal beans. In this study, we use image processing and machine learning techniques to discriminate the normal and peaberry bean as a part of the sorting system. As the first step, we applied Deep Convolutional Neural Networks (CNN) and Support Vector Machine (SVM) as machine learning techniques to discriminate the peaberry and normal bean. As a result, better performance was obtained with CNN than with SVM for the discrimination of the peaberry. The trained artificial neural network with high performance CPU and GPU in this work will be simply installed into the inexpensive and low in calculation Raspberry Pi system. We assume that this system will be used in under developed countries. The study evaluates and compares the feasibility of the methods in terms of accuracy of classification and processing speed.

Keywords: convolutional neural networks, coffee bean, peaberry, sorting, support vector machine

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Authors: Rita Alfattal, Maryam Alfarhan, Adeeb M. Algaith, Buthaina Albash, Reem M. Elshafie, Asma Alshammari, Ahmad Alahmad, Fatima Dashti, Rasha Alsafi, Hind Alsharhan

Abstract:

Defects of respiratory chain complex III (CIII) result in characteristic but rare mitochondrial disorders associated with distinct neuroradiological findings. The underlying molecular defects affecting mitochondrial CIII assembly factors are few and yet to be identified. LYRM7 assembly factor is required for proper CIII assembly where it acts as a chaperone for the Rieske iron‐sulfur (UQCRFS1) protein in the mitochondrial matrix and stabilizing it. We present here the seventeenth individual with LYRM7-associated mitochondrial leukoencephalopathy harboring a previously reported rare pathogenic homozygous LYRM 7 variant, c.2T>C, (p.Met1?). Like previously reported individuals, our 4-year-old male proband presented with recurrent metabolic and lactic acidosis, encephalopathy, and myopathy. Further, he has additional, previously unreported features, including an acute stroke like episode with bilateral central blindness and optic neuropathy, recurrent hyperglycemia and hypertension associated with metabolic crisis. However, he has no signs of psychomotor regression. He has been stable clinically with residual left-sided reduced visual acuity and amblyopia, and no more metabolic crises for 2-year-period while on the mitochondrial cocktail. Although the reported brain MRI findings in other affected individuals are homogenous, it is slightly different in our index, revealing evidence of bilateral almost symmetric multifocal periventricular T2 hyperintensities with hyperintensities of the optic nerves, optic chiasm, and corona radiata but with no cavitation or cystic changes. This report describes new clinical and radiological findings of LYRM7-associated disease. The report also summarizes the clinical and molecular data of previously reported individuals describing the full phenotypic spectrum.

Keywords: LYRM7 gene defect, mitochondrial disease, , lactic acidosis, , genetic disorder

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Authors: Chukwumeka Daniel Ezeliora

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The Nigerian manufacturing sector plays a pivotal role in the country's economic growth and development. However, it faces numerous challenges, including operational inefficiencies and inherent risks that hinder its sustainable growth. This research aims to address these challenges by exploring the integration of Lean and Six Sigma methodologies into the manufacturing processes, ultimately enhancing operational effectiveness and risk mitigation. The core of this research involves the development of a sustainable Lean Six Sigma framework tailored to the specific needs and challenges of Nigeria's manufacturing environment. This framework aims to streamline processes, reduce waste, improve product quality, and enhance overall operational efficiency. It incorporates principles of sustainability to ensure that the proposed methodologies align with environmental and social responsibility goals. To validate the effectiveness of the integrated Lean Six Sigma approach, case studies and real-world applications within select manufacturing companies in Nigeria will be conducted. Data were collected to measure the impact of the integration on key performance indicators, such as production efficiency, defect reduction, and risk mitigation. The findings from this research provide valuable insights and practical recommendations for selected manufacturing companies in South East Nigeria. By adopting sustainable Lean Six Sigma methodologies, these organizations can optimize their operations, reduce operational risks, improve product quality, and enhance their competitiveness in the global market. In conclusion, this research aims to bridge the gap between theory and practice by developing a comprehensive framework for the integration of Lean and Six Sigma methodologies in Nigeria's manufacturing sector. This integration is envisioned to contribute significantly to the sector's sustainable growth, improved operational efficiency, and effective risk mitigation strategies, ultimately benefiting the Nigerian economy as a whole.

Keywords: lean six sigma, manufacturing, risk mitigation, sustainability, operational efficiency

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Authors: Yu A. Pluttsova , O. V. Vakhnina , K. B. Zhogova

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Nowadays, many devices operate under conditions of enhanced humidity, temperature drops, fog, and vibration. To ensure long-term and uninterruptable equipment operation under adverse conditions, one applies moisture-proof films on products and electronics components, which helps to prevent corrosion, short circuit, allowing a significant increase in device lifecycle. The reliability of such moisture-proof films is mainly determined by their coating uniformity without gaps and cracks. Unprotected product edges, as well as pores in films, can cause device failure during operation. The work objective was to develop an effective, affordable, and profit-proved method for determining the presence of through defects of protective polymer films on the surface of parts made of iron and its alloys. As a diagnostic reagent, one proposed water solution of potassium ferricyanide (III) in hydrochloric acid, this changes the color from yellow to blue according to the reactions; Feº → Fe²⁺ and 4Fe²⁺ + 3[Fe³⁺(CN)₆]³⁻ → Fe ³⁺4[Fe²⁺(CN)₆]₃. There was developed the principle scheme of technological process for determining the presence of polymer films through defects on the surface of parts made of iron and its alloys. There were studied solutions with different diagnostic reagent compositions in water: from 0,1 to 25 mass fractions, %, of potassium ferricyanide (III), and from 5 to 25 mass fractions, %, of hydrochloride acid. The optimal component ratio was chosen. The developed method consists in submerging a part covered with a film into a vessel with a diagnostic reagent. In the polymer film through defect zone, the part material (ferrum) interacts with potassium ferricyanide (III), the color changes to blue. Pilot samples were tested by the developed method for the presence of through defects in the moisture-proof coating. It was revealed that all the studied parts had through defects of the polymer film coating. Thus, the claimed method efficiently reveals polymer film coating through defects on parts made of iron or its alloys, being affordable and profit-proved.

Keywords: diagnostic reagent, metal parts, polimer films, through defects

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Authors: Seyedeh Mozhgan Seyed-Talebi, Javad Beheshtian

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The toxicity of lead associated with the lifecycle of perovskite solar cells (PSCs( is a serious concern which may prove to be a major hurdle in the path toward their commercialization. The current proposed lead-free PSCs including Ag(I), Bi(III), Sb(III), Ti(IV), Ge(II), and Sn(II) low-toxicity cations are still plagued with the critical issues of poor stability and low efficiency. This is mainly because of their chemical stability. In the present research, utilization of all inorganic CsSnGeI₃ based materials offers the advantages to enhance resistance of device to degradation, reduce the cost of cells, and minimize the carrier recombination. The presence of inorganic halide perovskite improves the photovoltaic parameters of PCSs via improved surface coverage and stability. The inverted structure of simulated devices using a 1D simulator like solar cell capacitance simulator (SCAPS) version 3308 involves TCOHTL/Perovskite/ETL/Au contact layer. PEDOT:PSS, PCBM, and CsSnGeI₃ used as hole transporting layer (HTL), electron transporting layer (ETL), and perovskite absorber layer in the inverted structure for the first time. The holes are injected from highly stable and air tolerant Sn_0.5Ge_0.5I₃ perovskite composition to HTM and electrons from the perovskite to ETL. Simulation results revealed a great dependence of power conversion efficiency (PCE) on the thickness and defect density of perovskite layer. Here the effect of an increase in operating temperature from 300 K to 400 K on the performance of CsSnGeI₃ based perovskite devices is investigated. Comparison between simulated CsSnGeI₃ based PCSs and similar real testified devices with spiro-OMeTAD as HTL showed that the extraction of carriers at the interfaces of perovskite absorber depends on the energy level mismatches between perovskite and HTL/ETL. We believe that optimization results reported here represent a critical avenue for fabricating the stable, low-cost, efficient, and eco-friendly all-inorganic Cs-Sn-Ge based lead-free perovskite devices.

Keywords: hole transporting layer, lead-free, perovskite solar cell, SCAPS-1D, Sn-Ge based

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