Rework Process Research Articles

Environmental Signatures Preserved in Extremely Shallow-Water Benthic Foraminiferal Assemblages From Oman, Arabian Sea

Abstract The composition and preservation state of testate foraminiferal assemblages is of highest importance for paleoenvironmental and paleoclimatic reconstructions. Nearshore coastal areas, however, are often subject to harsh conditions, being shaped by continuous wave action and exposed to turbulence, erosion, and dynamic processes of sediment reworking. Situated at the interface between land and water, the environmental signatures preserved in assemblages of benthic foraminifera from coastal environments are therefore prone to taphonomic alterations, which potentially bias the fossil record and compromise accurate reconstructions. In this study, we have analysed the composition and preservation of benthic foraminifera from a suite of extremely shallow-water habitats along the Dhofar coastline (Oman) to document the structure of assemblages and illustrate their species richness. Our analyses show that extremely shallow foraminiferal assemblages from the southern coast of Oman retain the environmental signatures of their habitats despite intense environmental processes, making them useful for paleoenvironmental studies. Features of these signatures are recorded in the structural composition, species richness, dominance, and diversity indices of foraminiferal communities, in addition to numerical abundances of shell preservation groups.

Penurunan Lead Time Manufacturing Dengan Pendekatan Lean Manufacturing Studi Kasus Di PT. MKM

In the industrial world, it is very important to pay attention to the efficiency of production capacity where the manufacturing lead time for making shoe outsole is influenced by activities that are not value-added (Non Value Added) and activities that are not value-added but necessary (Necessary Non Value Added) in which there is some extravagance that occurs. These activities are in the form of temporary storage in the cooling room and the process of reworking defective products. The method used is Lean Manufacturing, the tools used are Value Stream Mapping (VSM) and Process Activity Mapping (PAM). VSM is used to identify activities that have cycle times exceeding takt time, followed by mapping the Activity Mapping process to analyze activities that are not Value Added. Based on the results of research from 4110 seconds, the process lead time of 3600 seconds is a non-value added activity. The rework process and material storage in the cooling room were identified as having the largest value contributing to lead time, so rework must be eliminated. the percentage of Process Cycle Efficiency (PCE) has increased. The reduction of the finished sheet material process is cooled to the cooling room and the rework process can save about 60 minutes of working time. Saving working hours can increase outsole production capacity so that productivity increases and targets are achieved.Keywords: Lead Time Manufacture, Lean Manufacturing, Value Stream Mapping, Prose Activity Mapping. Process Cycle Activity.

An amphibolitic source for “adakitic” I-type plutons in continental collision zones

Rocks with “adakitic” affinities are widespread in continental collision zones, recording important information about crustal thickening. Residual garnet during partial melting of the lower crust is traditionally considered to be responsible for heavy rare earth element and Y depletion, which is a key characteristic feature of these rocks. However, magmatic garnet is rarely observed in such adakitic igneous rocks and associated protolithic eclogite is also rarely reported. Instead, amphibole is a proposed abundant phase in lower arc crust. Whilst both garnet- and amphibole-rich assemblages can act as potential sources for intracrustal intermediate-silicic melts, their distinctive fractionation of fSm/Nd and fLu/Hf should, with time, lead to different Nd-Hf isotopic compositions in high Sr/Y rocks. Here we report whole-rock radiogenic Sr-Nd-Hf and stable Fe isotope compositions of well-characterized Oligocene to Miocene (33-14 Ma), post-collisional high-K adakitic intrusions from the Gangdese belt, South Tibet. The plutons have a low alumina saturation index and depleted Dy/Yb, pointing to negligible amounts of sediment contribution. They are characterized by variable initial 87Sr/86Sr ratios (0.7048 to 0.7078), mostly negative εNd (−4.9 to +0.3), positive εHf values (+1.5 to +8.3), and variable but heavy δ57Fe values ranging from +0.04 ± 0.08‰ to +0.35 ± 0.08‰. Modeling of Fe isotopes and fractionation factors of fSm/Nd and fLu/Hf indicate an amphibolite source. A Nd-Hf isotope correlation that is quasi-parallel to the mantle array can be best explained by the evolution of amphibolitic lower crust with a residence time of ca. 400 Myrs. Although these adakitic rocks have depleted, mantle-like Hf isotope compositions, they are part of an existing, older crustal foundation and thus represent a process of crustal reworking, instead of crustal growth. Therefore, proportions of mantle-derived materials that contributed to the Phanerozoic crustal growth based on Hf-in-zircon signatures alone may be overestimated. Combined mineral and whole-rock radiogenic and stable isotopes are required to address this issue in the future.

«PAR A QUE SE REPRESENTE ESTA COMEDIA APARENTE QUE HACE EL HUMANO SENTIDO»: REPRESENTAR LA COMEDIA HOY PAR A QUE NO SE OLVIDE EL AYER

Outside of festivals, the Comedia as a Golden Age cultural product is at risk of becoming an uprooted element in contemporary cul-ture. There are several phenomena against its integrated survival: the deconstruction of the concepts of “own” and “canonical,” the new gener-ations’ lack of identification, and the ethical and aesthetic processes of reworking and proximation. We propose here a didactic and informa-tive task that brings comedy (closer to its original conception) to general audiences through the creation of films in higher education institutions. As part of an educative digital humanities and public humanities proj-ect, these films would integrate an accessible repository of films based on comedies, facilitate interdisciplinary teaching, and provide the edu-cator with expressive means to teach and show the Comedia beyond the paper, in addition to providing students with experience-based learning.

Sensitivity Analysis of the Unrelated Parallel Machine Scheduling Problem with Rework Processes and Machine Eligibility Restrictions

Sensitivity Analysis of the Unrelated Parallel Machine Scheduling Problem with Rework Processes and Machine Eligibility Restrictions

Reconstructing the evolution of an ancient continental arc: Implications from the temporally-spatially related shoshonitic to calc-alkaline intrusive magmatism in the North China Craton

Coeval shoshonitic and calc-alkaline to high-K calc-alkaline rock series were discovered in the eastern North China Craton (NCC). Here, we report zircon and titanite UPb dating, zircon oxygen isotopic, whole-rock major and trace element and SmNd isotopic data for these rocks. Zircon and titanite UPb geochronology suggests that the coeval shoshonitic to calc-alkaline mantle-derived magmas from the Jinan terrane were emplaced at ∼2.5 Ga and recorded multi-phases of metamorphic imprints. The shoshonitic series in Group I show higher K2O, but in contrast, the calc-alkaline to high-K calc-alkaline series (Group II) are characterized by higher Na2O. The two groups have enriched light rare earth elements (LREE) and depleted/nearly flat heavy rare earth elements (HREE). They also show negative anomalies in some HFSE and positive anomalies in LILE. Therefore, the geochemical data, SmNd and O isotopes included, show that the Jinan shoshonitic to calc-alkaline magmas were generated by melting of the metasomatized mantle at an ancient continental arc. Distinct geochemical features possibly suggest different mantle source features (metasomatic agents). The elevated zircon δ18O values imply that the weathering was significant during the end of Archean. In addition, the crustal reworking or intra-crustal recycling process played an important role in the continental crust evolution. The low-δ18O magmas documented here possibly indicate high-temperature water-rock interaction that occurs between continental crust and meteoric water. This study represents an example of co-existed shoshonitic and calc-alkaline mantle-derived magma derived from the melting of metasomatized mantle above an ancient subduction zone. Similar coeval associations of shoshonitic to calc-alkaline mantle-derived rocks, in combination with high-P granulites and crust-derived granites, may be used to constrain the ancient subduction-collisional belts.

Reducing Manufacturing Lead Time With Lean Manufacturing Approach Case Study: CV Suho Garmindo

The purpose of this study is to reduce the Lead Time Manufacturing of mask products at CV Suho Garmindo. At this time it is known that Lead Time Manufacturing is influenced by Non-Value-Added activities and Necessary Non-Value Added activities in which there are several wastes that occur, these activities include the temporary storage process in the loading section, the process of reworking defective products and the transportation process. The method used is Lean Manufacturing, the tools used are Value Stream Mapping (VSM) and Process Cycle Activity (PAM). Value Stream Mapping is used to identify activities that have a cycle time greater than the takt time, followed by Process Cycle Activity mapping to analyze activities that are Non-Value Added activities. Furthermore, NVA activities are analyzed with 5W1H, and 5 why's tool to find out the root of the problem. Based on the research results from 126.1 minutes of lead time process 110 minutes is a non-value added activity. The rework process is identified as having the largest value of contributing lead time, so rework must be eliminated. After it is known that the root cause of the rework process is due to the ineffectiveness of the sewing process (bottleneck occurs), then for improvement the author proposes the needs of the available machines and man power. The changes are the number of machines from 9 to 10, sonday operators from 2 people to 1 person, finished stick operators from 2 people to 1 person, and funnel operators from 2 people to 4 people. Furthermore, the optimal layout improvement based on production flow is described. Due to research limitations, this research did not reach the implementation stage. So with the change in the number of machine requirements and available man power, it is expected that the rework process will be reduced so that the Manufacturing Lead Time can be reduced.

Performance evaluation and optimization model for closed-loop production lines considering preventive maintenance and rework process

Closed-loop production lines with a constant number of carriers are widely encountered in today's production systems. In this paper, a production performance evaluation and optimization model is proposed for a closed-loop production line taking into account the degradation-level-dependent quality and rework process. Based on a two-machine-one-buffer decomposition method and the system state transition, a production performance evaluation method is presented. Due to the emphasis on quality management, preventive maintenance (PM) is used to ensure the reliability of the machines in the production line, increasing the effective output at minimum cost. A hybrid particle swarm optimization and estimation of distribution algorithm (PSO-EDA) is proposed to efficiently develop the optimal PM strategy. Finally, numerical experiments are performed to verify the effectiveness of the model. With the objective of maximizing the system profit, the optimization of the machines and pallets number is also explored.

Generation of the Early Cretaceous granitoid in the Dazeshan region, Jiaodong Peninsula: Implications for the crustal reworking in the North China Craton

Lower crust-derived granitic rocks provide constraints on the crustal reworking process and consequently give hints on the destruction mechanism of the cratons. The North China Craton (NCC) underwent extensive crustal melting in the Mesozoic. This study investigated granitic intrusions in the Dazeshan region of the Jiaodong Peninsula. Whole-rock major and trace element analyses and zircon U-Pb ages coupled with Hf isotopes were used to reveal the crustal reworking processes. Zircons separated from the quartz porphyry, Linglong granite, rhyolite porphyry, and biotite granite showed weighted mean 206Pb-238U ages of 119.2 ± 1.0 Ma, 140.2 ± 1.0 Ma, 120.6 ± 0.5 Ma, and 119.9 ± 0.7 Ma, respectively. The quartz porphyry, rhyolite porphyry, and biotite granite had high silica contents (SiO2 = 74–77 wt.%) but low MgO, Co, and Ni concentrations. The calculated εHf(t) values for the rhyolite porphyry and the biotite granite ranged from −18.3 to −20.0 and −17.8 to −20.2, respectively. These geochemical features imply ancient crust sources. The quartz porphyry showed distinct primitive mantle-normalized rare earth element (REE) patterns and was characterized by lower ΣREE content and lack of pronounced negative Eu anomalies. Whole-rock and zircon Dy/Yb ratios showed no correlation with whole-rock Rb/Sr ratios and zircon Hf contents, reflecting limited effects of crystal fractionation. The Ba/La ratios were also high (>150), but the Sr/Y and La/Yb ratios were low (Sr/Y < 50; La/Yb < 15). These features likely indicate that the quartz porphyry was generated by water-fluxed melting without differentiation. The rhyolite porphyry and biotite granite shared many geochemical similarities, denoting a unified source. The high La/Yb (>30) but low Sr/Y (<20) ratios and apparent negative Eu anomalies indicated plagioclase fractionation. Decreased zircon Dy/Yb with increasing Hf concentrations reflected noticeable amphibole fractionation. These two suites had fairly low Ba/La ratios. These data together point toward an identical source: dehydration melting of a relatively thickened crust. These melts experienced crystal fractionation after extraction. We propose that the intrusions were generated by the underplating of water-rich mafic magma, which provided both fluid and heat and finally induced two kinds of melting.

Indelible marks: Beth Harland’s absorption

ABSTRACT The article traces Beth Harland's approach to painting practice in light of her engagement with Michael Fried's interpretation of eighteenth and nineteenth century painting and her fascination with Marcel Proust's À la recherche du temps perdu. The contrast between reflection on phenomena of inner life and a painting’s audience address is explored through a reading of passages from Nietzsche’s The Gay Science, Proust's Contre Sainte-Beuve and Fried's writing about theatricality and absorption. Harland’s practical and theoretical explorations of the situation and possibilities of contemporary painting, illuminated by her engagement with notions of theatricality and absorption, are then outlined. After considering Hans Belting’s views on seriality and processes of re-working, the article concludes by suggesting that Harland sought and achieved a buoyant working relationship between formational contraries, avoiding both hypostatisation and easy compromise.

Replenishment-shipment decision for a multiproduct producer-client coordinated FPR model with postponement, rework and subcontracting

This research constructs a mathematical scheme to explore replenishment-shipment decisions for a multiproduct producer-client coordinated finite production rate (FPR) model with the postponement, rework, and subcontracting plan. The considered multiple goods have a common component, and a batch FPR fabrication with postponement is planned to meet the annual multiproduct requirements. The first fabricating phase makes only the standard components needed for a batch and subcontracts a proportion of them (with additional cost) to expedite the process. In contrast, the second fabricating phase produces the finished multiple merchandise in sequence. The in-house rework processes with extra expense help retain the desirable quality. Each merchandise’s finished batch is transported to the clients in equal-sized numerous shipments. This study derives the optimal batch cycle length and transporting frequency by minimizing the overall fabricating-shipment expenses (including clients’ holding costs). This work offers a numerical example demonstrating various crucial system features influenced by the factors of subcontracting, postponement, rework, and transportation policies to facilitate managerial decision making in industries.

Geochemistry and petrogenesis of the Paleoproterozoic ortho-gneisses and granitoids of the Banded Gneissic Complex, central Rajasthan, NW India: Implications for crustal reworking processes

Geochemistry and petrogenesis of the Paleoproterozoic ortho-gneisses and granitoids of the Banded Gneissic Complex, central Rajasthan, NW India: Implications for crustal reworking processes

A Sustainable Production Scheduling with Backorders under Different Forms of Rework Process and Green Investment

Rework is currently a necessity for businesses and commercial organizations across the world. It is only beneficial in tackling climate change if the process emits less greenhouse gases than would otherwise be emitted. This study designs an optimal production scheduling model to reduce both carbon emissions during the processes of production, transport and storage, and setup cost by leveraging on green technology efforts in an imperfect production process where a fraction of items is erroneous so that the firm may run out of inventory. The producer implements a rework strategy to rectify the flawed products, anda flexible rework rate is offered since the rework might be executed on various schemes. The flexible rework allows the producer to choose therework rate, which can differ from the production rate, as well as the rework process itself, which can be asynchronous or synchronous.The two forms of green investments: quadratic and exponential are considered in the study. The main point of the study is to derive a solution procedure of the various problem settings associated with the rework rate, rework process and green investment. The findings suggest that developing the optimal production schedule (lot-sizes, backorders, setup cost and green investment amount) can lower the manufacturing sector’s excessive ecological carbon emissions. The findings also support the idea that making green investments is the most cost-effective way to cut carbon emissions and setup cost simultaneously.

Identification of Jurassic pure sediment-derived granites in the Central Lhasa Terrane, Tibetan Plateau: Implications for continental crustal reworking during Mesozoic Tethyan subduction

A bstract Pure sediment-derived granite, a recently recognized crustal geochemical end-member, is relatively rare but provide primary access to probe the process of continental crustal reworking. This paper presents geochemical and geochronological data for granites emplaced in the Asuo area within the central Lhasa Terrane of the Tibetan Plateau at ca. 158 Ma (zircon U − Pb isotopic dating). These granites are two mica-bearing and contain high SiO 2 (75.40–79.11 wt%), high A/CNK (1.06–1.33), heterogeneous ( 87 Sr/ 86 Sr) i (0.705519–0.710891), and relatively uniform and low ε Nd (t) (−13.18 to −14.81) values, which are analogous to typical S-type granites. The low ε Hf (t) (−13.98 to −12.08) and high δ 18 O (8.01‰–8.85‰) values of magmatic zircons, the similar of ε Nd (t) values between the Asuo granites and regional Jurassic slates, and the absence of mafic enclaves, verify that these granites were derived from a pure sedimentary source. The trondhjemitic features, low CaO/Na 2 O (<0.1) and molar CaO/(MgO + FeO T ) (0.06–0.58), relatively constant and low Rb/Sr (0.04–0.32), as well as the heterogeneous ( 87 Sr/ 86 Sr) i ratios, indicate that the Asuo granites formed via fluid-present muscovite-dehydration melting of metapelitic protoliths, with mica as the main residue. Combined with a synthesis of existing tectonomagmatic data on the Lhasa Terrane, we propose that the Jurassic Asuo granites were formed in a continental extensional setting associated with the northward subduction of the Neo-Tethyan lithosphere. The present study highlights that the inboard region of an active subduction zone is probably an important site of crustal reworking, and provides a geochemical end-member of pure sediment-derived melts for the central Lhasa Terrane. • Jurassic two-mica granites are discovered in the Asuo Area of central Lhasa Terrane; • The Asuo granites were derived from a pure sediment protolith of pelite; • The rear-arc region of a subduction zone is an important site for crustal reworking.

THERMAL-INDUCED DAMAGE ON SOLDER JOINTS OF HIGH-DENSITY ADJACENT BALL GRID ARRAY COMPONENTS DURING THE REWORK PROCESS

Correlation between adjacent ball grid array (BGA) components' temperature and thermal-induced damage to their solder joints on both the top and bottom printed circuit board assembly (PCBA) sides during the rework process is studied in this work. Total often adjacent BGA components from the rework area on the top (F - K) and bottom (A - E) PCBA side were observed. The dye and pull (D&amp;P) test results, infrared thermography images, and temperature measurements were analyzed for solder joint crack induced by the thermal damage with precise temperature measurement on each adjacent BGA component. Scanning electron microscope (SEM) analysis complemented the post-D&amp;P test solder joint crack observation. The D&amp;P test results shows that 76 % or higher and solder joint separation locations at the copper pad on BGA occurred when the temperature of the adjacent components of the rework location exceeded 195 °C and 210 °C on the centre and corner of the component, respectively.

Study on Implementation of Lean Six Sigma in Hospital Auxiliary Ship Block Construction Process

During the pandemic, transportation is needed to support the evacuation of patients through waterways; therefore, PT PAL Indonesia (Persero) has created a Hospital Auxiliary Ship project. In building a quality Hospital Auxiliary ship project, productivity is needed so the project can be completed properly. However, there are problems with the punctuality of completing the ship block construction with a total lead time of 19200 minutes and found the block quality is not up to standards like Surface Porosity, Former Stopper, Arc Strike, and Low Bead defects that require a rework process and cause long cycle times. This study aims to reduce the lead time value and minimize waste or activities that are not value-added using the lean six sigma method with stages (DMAIC). From the results of the study, it was found that the identification of the Process Activity Mapping (PAM) design, which resulted in the highest waste rating, namely 16.94% defect, with CTQ-4, lean six sigma value of 3.055 sigma and DPMO value of 59917 which was included in the excellent category for the industry average. The factors causing the problem were identified with Pareto diagrams and causal diagrams to determine the dominant type of defect and the causes of wastage of defects; there are four factors, namely material, human, machine, and environment. Recommendations for the improvement of waste are through material inspection, operator training, reworking defective blocks, and minimizing non-value-added activities. With the design of process activity mapping (PAM) and value stream mapping, the efficiency of ship block construction can increase from 67.81% to 74.06%.

Orogenic reworking and reactivation in Central Iberia: A record of Variscan, Permian and Alpine tectonics

Interference between orogenic systems and deformation phases within them may lead to reworking and reactivation of previous structures. The eastern sector of the Spanish-Portuguese Central System holds evidence of two orogenic systems, Variscan and Alpine, plus a stage of Permian extension. We perform an integrated structural analysis to identify reworking and reactivation processes throughout the geological record. The Variscan record starts with crustal thickening (D1; E-verging overturned folds). A second phase features the intra-orogenic collapse of an overthickened crust (D2; top-to-the-SE ductile extensional shear zone), which produced intense structural reworking at the core of the shear zone and moderate reworking at its hanging wall. During subsequent strike-slip tectonics, crustal thickening parted transpressional deformation into a dextral shear zone and upright folds (D3). Variscan deformation did not reactivate previous structures, but exploited a weak rheological boundary defined by contrasted lithologies (sedimentary versus igneous rocks) to accommodate D2 shearing. Reactivation played a role afterwards: Variscan strike-slip shear zone acted as a transfer fault to accommodate Permian extension (post-orogenic collapse), and then Alpine contraction. The Permian extension record is blurred by Alpine inversion, although the trend of Alpine structures in Central Iberia, and the Spanish-Portuguese Central System, may result from Permian structural inheritance.

A production-inventory model under quality-maintenance policy with rework process in the presence of random failures and multiple assignable causes

ABSTRACT This research presents simultaneous design of production planning, maintenance strategy and control chart in which two issues are considered: (1) multiple assignable cause and (2) equipment failure. The first one means that various factors may shift the process to an out-of-control state; while the second one means that the equipment is not always available and may be suddenly failed. Also, to reduce the production costs, a rework process is performed on the nonconforming items right after the regular cycle. Furthermore, three types of maintenance activities are applied based on system conditions. The corrective maintenance is conducted when the equipment failure occurs. The preventive maintenance is accomplished when the process continues until the end of the cycle, and the predictive maintenance is performed whereas the chart issues a true alarm. To check the effectiveness of the model, three comparative studies are examined. The first one compares the suggested model with a similar model without the rework process; the second one demonstrates the importance of employing the statistical process monitoring; and the last one compares the model with a similar model without considering the equipment failure. The results show the superiority of the integrated model compared to the others in the cost-saving.

Organic molecular evidence in the ∼1.40 Ga Xiamaling Formation black shales in North China Craton for biological diversity and paleoenvironment of mid-Proterozoic ocean

Indigenous hydrocarbon biomarkers in the black shales of the 1.40 billion-year-old Xiamaling Formation (XML) from the North China Craton were systematically analyzed to reveal the redox condition and biological community. These black shales are not only rich in organic matter, but also undergone an unexpectedly low thermal evolution process, both of which contribute to well-preserved indigenous hydrocarbons and promote the convincing discovery of the Precambrian biology. The combination of the absence or low concentrations of gammacerane, dibenzothiophene series and aryl isoprenoids, abundant rearranged hopanes, the occurrence of micro-ripples, and low level of redox-sensitive trace elements suggested shallow, low salinity and suboxic to anoxic conditions during the deposition period of XML. The absence of aryl isoprenoids as diagnostic biomarkers for green/purple sulfur bacteria strongly argued against the pervasively euxinic (sulphidic) bottom water in mid-Proterozoic ocean. The scenario of large hump unresolved complex mixture and abundant monomethyl alkanes as well as absent steranes may be derived from benthic microbial reworking processes for biolipids. Here the absence of saturated and aromatic steroids in the XML sediments suggested that eukaryotic algae have little ecological contribution to primitive biomass and/or are the result of heterotrophic reworking from benthic microbial mats. Abundant presence of hopanoid, tricyclic terpane and n-alkane in these samples supported the predominant contribution of (cyano) bacteria.

Effect of heat shield locations on rework-induced thermal management in ball grid array solder joint

This study investigated the effectiveness of heat shield placement locations during the rework process to avoid thermal and mechanical damage to adjacent ball grid array components and their solder joints on double-sided printed circuit board assembly. Three types of heat shield placement locations were used: sample X, individual heat shield placement on adjacent components of the rework location; sample Y, a U-shaped, and sample Z, a square-shaped heat shield placed respectively at the heat source location. The dye and pull test results, infrared thermography, and temperature measurements were analysed to understand the relationship between the location of the heat shield and solder joint damage during rework. Heat shield placement at the heat source location on the reworked component can reduce the peak temperatures on the adjacent rework component locations by up to 8.18%. The peak temperatures of the centre and corner of the BGA component can be maintained below 195 °C and 210 °C, respectively to improve the adjacent rework component locations' solder joint quality by reducing solder joint damage by more than 50% solder cracks. This is useful for thermal management during rework involving high-density ball grid array component placements on double-sided printed circuit board assembly.