Hard Parts Research Articles

A review of surface integrity in machining of hardened steels

Abstract This paper presents a background of surface integrity in the machining of hardened steels for rolling dies, moulds, bearings, shafts, gears, etc. Hardened steels, which are normally harder than 45 HRC, are considered difficult to cut owing to their combinations of mechanical and physical properties that promote low chip–tool contact area and high forces, and in turn, result in high contact stresses and elevated temperatures. In particular, the high temperatures generated on a newly machined workpiece surface can promote poor surface integrity, such as white layers and microcracks, warping, and consequently reduced fatigue strength. Additionally, tool wear is often significant, which further exacerbates the problem of high cutting temperatures, leading to frequent rejection of hard machined parts during quality control and thus increased manufacturing costs. In this work, the background of surface integrity during machining of hardened steels is introduced, and the main challenges and their solutions from the literature are discussed based on a diverse set of case studies. Based on the state of the art, a series of conclusions and best practices are presented, in addition to an outlook on future directions in the field of machining-induced surface integrity of hardened steels.

The role of gastropod shell composition and microstructure in resisting dissolution caused by ocean acidification

Organisms, such as molluscs, that produce their hard parts from calcium carbonate are expected to show increased difficulties growing and maintaining their skeletons under ocean acidification (OA). Any loss of shell integrity increases vulnerability, as shells provide protection against predation, desiccation, and disease. Not all species show the same responses to OA, which may be due to the composition and microstructural arrangement of their shells. We explore the role of shell composition and microstructure in resisting dissolution caused by decreases in seawater pH using a combination of microCT scans, XRD analysis, and SEM imaging. Two gastropods with different shell compositions and microstructure, Tegula funebralis and Nucella ostrina, were exposed to simulated ocean acidification conditions for six months. Both species showed signs of dissolution on the exterior of their shells, but changes in density were significantly more pronounced in T. funebralis. XRD analysis indicated that the exterior layer of both shell types was made of calcite. T. funebralis may be more prone to dissolution because their outer fibrous calcite layer has more crystal edges and faces exposed, potentially increasing the surface area on which dissolution can occur. These results support a previous study where T. funebralis showed significant decreases in both shell growth and strength, but N. ostrina only showed slight reductions in shell strength, and unaffected growth. We suggest that microstructural arrangement of shell layers in molluscs, more so than their composition alone, is critical for determining the vulnerability of mollusc shells to OA.

Morphometric and genetic evidence for cryptic diversity in Gyrodactylus (Monogenea) infecting non-native European populations of Ameiurus nebulosus and A. melas.

Gyrodactylid parasites were observed on non-native populations of North-American freshwater catfishes, Ameiurus nebulosus and Ameiurus melas (Siluriformes: Ictaluridae), at several sites in the Elbe River basin, Czech Republic, Europe. Using a combination of morphological and genetic analyses, the parasites infecting A. nebulosus were determined to be Gyrodactylus nebulosus, a North American parasite co-introduced to Europe along with its Ameiurus fish hosts. Subtle morphometrical differences, as well as seasonal variations, were observed among parasites collected from A. nebulosus and A. melas. The host-related variation was further supported through genetic analysis of the partial 18S rDNA, ITS1-5.8S-ITS2 and COI, showing 0.2, 3.0 and 4.8% divergence, respectively. Consistent genetic differences indicated there were two distinct genotypes. Subtle morphological differences associated with the shape of sickle toe, anchor root and ventral bar membrane, according to host species, also supported the description of a new cryptic species, Gyrodactylus melas n. sp., infecting A. melas. Multivariate morphometrical analysis of haptoral hard parts showed significant differences between the anchor lengths of G. nebulosus and G. melas n. sp. However, the measurements of the haptoral hard structures partially overlapped between species, limiting the usage of these parameters for species delineation.

Change is Hard: Leadership is Harder.

The transformation of the Military Health System to the Defense Health Agency under the National Defense Authorization Act of 2017 is a change of historical proportion. Change can be seen as hard, yet change is always happening. What is actually hard is providing leadership to accomplish the mission and goals for ourselves and our organizations within constant change. Those of us selected for leadership positions often receive standardized preparation and experiences to help us with this challenge. The hard part, though, is not what we often think it is. Leadership is not hard because of the amount of change or the people we are leading. Leadership is hard because, as we increase our rank and responsibilities, there are more people we need to see as people, having an outward mindset toward them, to have a positive influence and impact. In this article, I share the challenge I experienced with an outward mindset in leading the transition of our military treatment facility under the transformation to Defense Health Agency.

Experimental Study on Electrodes Types in Electrical Discharge Machining (EDM) of High-Speedd Steel

Electrical Discharge Machining (EDM) is widespread Nontraditional machining (NTM) Processes for manufacturing complicated geometry or very hard metals parts that are difficult to machine by traditional machining operations. Electrical discharge machining is a material removal rate (MRR) process characterized by using electrical discharge erosion. This paper discusses the optimal parameters of EDM on high-speed steel (HSS) AISI M2 as a workpiece using copper and brass as an electrode. The input parameters used for experimental work are Current (10, 24 and 42 A), Pulse duration (100, 150 and 200 µs), and Pulse pause-Time (4,12, and 25 µs) that effect on the material removal rate (MRR), and Electrode Wear Rate(EWR). A Minitab (17) software environment to adopt the Full Factorial Method method to analyze the effect of input on the response of EDM. The results showed that the higher value of MRR and the lower value of EWR offered via the copper electrode. The most influential factor that effect the process response (MRR, and EWR) is pulse current.

Forest Fire and Trespassing Detection using WSN with PIR sensor

Fire occurring in forest has become a major crises, the hard part of this is passing information about fire occurred is delay which in turn allow to increase the spread of fire. There are two preeminent reasons on delay, first is place or region in which fire has occurred and the other is passing information about fire to outer world. Forest fire can be controlled using appropriate technique and officials can control the wild fire before spreading, if the information is passed fast. Human trespassing is one of the dominant acumen for wild fires. In order to know the type of the fire depending upon the region and also deportation of data about fire occurred, we framed a lay out, forest fire detector that uses wireless sensor networks. The detector is able to inform us whether it is a crown fire or ground fire depending upon the region using fire sensors and PIR via NodeMCU ESP8266. PIR is used to detect the presence of humans within the preserved regions of wild. The detectors that are connected to the NodeMCU pass the information to tan other NodeMCU using server client configuration. Depending on the type of fire, sprinklers are activated to control ground fire and drones carrying fire resistant dry chemicals are used to spread them from above for crown fire.

Four New Species of Synodontella Dossou et Euzet, 1993 (Monogenea: Dactylogyridae) Gills Parasites of Synodontis clarias from the Bagoué River (North-Western Ivory Coast).

A survey of monogenean parasites on the gills of Synodontis clarias was carried out in Ivory Coast. Five species of monogeneans were found, of which four are new to science and are newly described here. The monogeneans were individually isolated from the gill and transferred directly onto a slide in a drop of glycerin ammonium picrate mixture (GAP). The haptor and the hard part of the copulatory complex were measured and drawings made using Motic BA310 microscope and Motic Image Plus 2.0 and Corel Draw software. Five species of Synodontella including four new to science were described. Synodontella anohmangniae n. sp., Synodontella antoineparisellei n. sp., Synodontella clariasi n. sp. and Synodontella samorossoensis n. sp. differ from the previously described Synodontella species mainly in the morphology of their male copulatory organs (MCO). Synodontella anohmangniae n. sp. is distinguishable by the dorsal transverse bar with a small point at each extremity of the concavity in its central part. Synodontella antoineparisellei n. sp. differs from all other known Synodontella spp. in the morphology of the penis, with an egg-shaped opening in its distal part. Synodontella clariasi n. sp. and Synodontella samorossoensis n. sp differs from all other described congeneric species mainly by the dorsal transverse bar surmounted by a highly sclerotized part.

TRADUÇÃO] ENFRENTANDO O PROBLEMA DA CONSCIÊNCIA

To make progress on the problem of consciousness, we have to confront it directly. In this paper, I first isolate the truly hard part of the problem, separating it from more tractable parts and giving an account of why it is so difficult to explain. I critique some recent work that uses reductive methods to address consciousness, and argue that such methods inevitably fail to come to grips with the hardest part of the problem. Once this failure is recognized, the door to further progress is opened. In the second half of the paper, I argue that if we move to a new kind of nonreductive explanation, a naturalistic account of consciousness can be given. I put forward my own candidate for such an account: a nonreductive theory based on principles of structural coherence and organizational invariance, and a double-aspect theory of information.

Probing the Higgs–strange-quark coupling at e+e− colliders using light-jet flavor tagging

We propose a method to probe the coupling of the Higgs to strange quarks by tagging strange jets at future lepton colliders. For this purpose we describe a jet-flavor observable, $J_F$, that is correlated with the flavor of the quark associated with the hard part of the jet. Using this variable, we set up a strangeness tagger aimed at studying the decay $h\to s\bar{s}$. We determine the sensitivity of our method to the strange Yukawa coupling, and find it to be of the order of the standard-model expectation.

High-frequency lengthwise diffraction by the curve separating soft and hard part of the surface

The paper examines the model problem of high-frequency diffraction by a convex surface consisting of two parts. One is soft, the other is hard. The incident wave falls at a small angle to the line which separates soft and hard parts of the surface. The change in the boundary condition provokes the field in the Fock zone to have a rapid transverse variation. This causes a special boundary-layer to be formed. The boundary value problem for the three dimensional parabolic equation is reduced to the Riemann problem solved by the factorization in the form of infinite products containing the zeros of the Airy function and zeros of its derivative. the results of this factorization appear under the sign of double Fourier integral in the representation of the field. Both numerical and asymptotic analysis of this representation is carried out and illustrates the effects of high-frequency diffraction caused by the line of the boundary condition discontinuity.

Characteristics of the grey seal (Halichoerus grypus) diet in the Vistula River mouth (Mewia Łacha Nature Reserve, southern Baltic Sea), based on the osteological and molecular studies of scat samples

• Seals eat the soft part of fish but omit head of cod and salmon in their diet. • High frequency of occurrence of river lamprey ( Lampetra fluviatilis ) has been identified in the diet of the investigated grey seals • Presence of certain fish species in the diet is affected by the availability of these species • Diet of the seals in the mouth of the Vistula River include a mixture of both freshwater and marine fish species The study analyses for the first time the diet composition of grey seals inhabiting the Polish Baltic Sea coast. Samples of seal scat were collected in the Mewia Łacha Nature Reserve at the mouth of the Vistula River. Using genetic and osteological methods, the remains of organisms included in the grey seals diet were analysed for their taxonomy (families and species). Based on the analysis of 49 scat samples from grey seals, 761 hard parts that could be identified by taxon were isolated. The predominant species in the samples were perch, Perca fluviatilis (almost 78% of samples); pikeperch, Sander lucioperca (67%); lamprey, Lampetra fluviatilis (almost 35% of samples); Baltic cod, Gadus morhua callarias (almost 31% of samples) and sea trout, Salmo trutta trutta (26.5%). Genetic analysis confirmed the presence of Atlantic cod DNA in 69% and sea trout in 63% of samples. The genetic material of the Atlantic herring, Clupea harengus has not been identified in the analysed scat samples. Information on grey seals feeding on river lampreys seems to be valuable in the context of lack of knowledge on the occurrence of lampreys in the Vistula River. The methodology used showed that seals fed on species that were the most abundant in the area which is directly associated with the migration cycle of fish. The results of our study allowed the conclusion that the grey seal is an opportunistic predator and its diet reflects and exploits the variations in its habitat.

THE BEHAVIOR AND PATTERN OF SOIL CRACKS AND ITS MANAGEMENTS IN VERTISOLS

Soil cracks are an important physical property of expanded clay soils accompanied by distinctive morphological features such as Galgi and Silkensides as a result of the expansion and contraction processes by moistening and drying the soil which effect on water movement and its flow into the soil body, Three experiments were conducted to study the pattern of soil cracks formation and to show the extent of the effect of adding sand and sheep residues on the cracks forms. Some morphological characteristics resulted from the cracking process such as Number of separate pieces, Cracks length, Cracks width, Thickness of hard part, Area of cracked pieces and Crack pattern were calculated in this study. The morphological description of the cracks showed a clear difference in their forms and the width of the cracks in proportion to the depth of the cracks with their width. The results showed a decrease in the width and length of the cracks with an increase in the addition of sand and sheep residues. Significant differences appeared in values of Crack Intensity Factor (CIF) when adding sheep residues by 6% compared with 6% sand and control treatment. The value of CIF was (2.25%, 2.60% and 3.78%) for sheep residues, sand and control respectively, thus it affected the behavior and pattern of soil cracks.

Predatory protists.

The vast majority of eukaryotic life is made up of single cells commonly referred to as protists. In this primer, Leander provides an introduction to predatory protists - cells that eat other cells. This lifestyle, in particular the use of phagocytosis, makes endosymbiosis possible and enabled the evolution of complex cells.

Inferring diet, feeding behaviour and causes of mortality from prey-induced injuries in a New Zealand fur seal.

New Zealand fur seals Arctocephalus forsteri are the most abundant of the 4 otariid (eared seal) species distributed across Australasia. Analyses of stomach contents, scats and regurgitates suggest a diet dominated by bony fish and squid, with cartilaginous species (e.g. sharks and rays) either absent or underrepresented because of a lack of preservable hard parts. Here we report on a subadult specimen from south-eastern Australia, which was found ashore emaciated and with numerous puncture wounds across its lips, cheeks, throat and the inside of its oral cavity. Fish spines embedded in the carcass revealed that these injuries were inflicted by chimaeras and myliobatiform rays (stingrays and relatives), which matches reports on the diet of A. forsteri from New Zealand, but not South Australia. Shaking and tearing of prey at the surface may help to avoid ingestion of the venomous spines, perhaps contributing to their absence from scats and regurgitates. Nevertheless, the number and severity of the facial stab wounds, some of which led to local necrosis, likely affected the animal's ability to feed, and may account for its death. Despite their detrimental effects, fish spine-related injuries are difficult to spot, and may be a common, albeit cryptic, type of trauma. We therefore recommend that stranded seals be systematically examined for this potentially life-threatening pathology.

Perancangan Sistem Pakar Penyakit Gigi Menggunakan Metode Forward Chaining Pada Klinik Pratama Condet

Teeth are hard parts in the mouth. The tooth has a varied structure that functions as a cutter, renderer and food chewer. If the tooth is not cleaned after eating, it can cause bacteria to appear. Where these bacteria can damage teeth and cause a person to get dental disease. In addition to teeth is a tool for digestion of food, teeth are also a person's appearance. This display is very much needed and someone needs to meet face to face with other people. When cavities, will automatically reduce one's appearance. Moreover, cavities are accompanied by toothache, this can interfere with one's activities in doing work. expert system which is an artificial intelligence program that combines the base of the knowledge base with an inference system to imitate an expert. It is also a system that seeks to adopt human knowledge to computers, so that computers can solve problems as is usually done by experts. Forward Chaining is a decision-making strategy that starts from the fact to the final conclusion. Then monitoring uses an internet connection to connect to the web. Key Word : Dental Disaese, Expert System, Forward Chaining, Web

"The Hardest Part is What to Leave Behind…": Trauma, Medicine, and the Common Goals of Winnie the Pooh and The Story of Dr. Dolittle Abstract.

On an initial read, neither A.A. Milne's Winnie the Pooh Adventures or Hugh Lofting's The Story of Dr. Dolittle come across as literature written about trauma, and yet both stories derived from authors who were at the front lines of World War I and who put their war experiences into their stories. Evoking nostalgia and drawing on simple lore, both of these works continue to touch the human psyche. Both writers reinvented the way we see trauma and pain, whilst advocating for broader access to holistic healthcare. This, in turn, has impacted our relationship with trauma texts and healthcare forever.

How Did I Feel Before Becoming Diabetes Resilience? A Qualitative Study in Adult Type 2 Diabetes Mellitus

Introduction: Diabetes resilience is a condition where people with diabetes can accept their incurable disease as well. It is characterized by regular blood sugar, a diet-controlled, active, and not stressful. However, various kinds of feelings must be passed to become diabetes resilience. The study aimed to know what adult type 2 diabetes mellitus (T2DM) felt before becoming resilient. Methods: A qualitative phenomenology design was conducted to observe the experience of adult T2DM before becoming resilient. The total participants were ten T2DM patients obtained through snowball sampling. The data collection was conducted through in-depth interviews with interview guidelines and analyzed using qualitative thematic analysis. Results: The results of the study found two major themes namely psychological response and diet. Participants felt quite severe stress when diagnosed with diabetes mellitus and felt difficulty when undergoing diabetes mellitus treatment. In addition, changes in diet are also felt very difficult by participants in undergoing a diabetes mellitus diet. Conclusions: Psychological responses and diet are the hard parts felt by the participants. Increasing understanding, support, and acceptance can be one strategy to increase diabetes resilience in participants.

Six new species of Cichlidogyrus Paperna, 1960 (Platyhelminthes: Monogenea) from the gills of cichlids (Teleostei: Cichliformes) from the Lomami River Basin (DRC: Middle Congo)

BackgroundMonogenea van Beneden, 1858 is a group of parasitic flatworms, commonly found infecting bony fish. Several genera, such as Cichlidogyrus Paperna, 1960, are reported to include potential pathogenic species that can negatively impact aquaculture fish stocks. They can switch from introduced to native fish and vice versa. In Africa (and all over the world), fish species belonging to Cichlidae are often kept in aquaculture and represent a major source of food. Thus, research on the biodiversity and occurrence of monogenean species on these fish is of importance for aquaculture and conservation. The present study is a survey of the diversity of species of Cichlidogyrus in the south of the Democratic Republic of the Congo (DRC) on three cichlid species: Orthochromis sp. ‘Lomami’, Serranochromis cf. macrocephalus, and Tilapia sparrmanii Smith, 1840.MethodsSpecimens of Cichlidogyrus were isolated from the gills and mounted on glass slides with Hoyer’s medium. The genital and haptoral hard parts were measured and drawn using interference contrast.ResultsIn total, six species of Cichlidogyrus were found, all new to science: C. bulbophallus n. sp. and C. pseudozambezensis n. sp. on S. cf. macrocephalus, C. flagellum n. sp. and C. lobus n. sp. on T. sparrmanii, C. ranula n. sp. on S. cf. macrocephalus and Orthochromis sp. ‘Lomami’, and C. maeander n. sp. found on Orthochromis sp. ‘Lomami’ and T. sparrmanii. The first four species are considered to be strict specialists, C. ranula n. sp. an intermediate generalist and C. maeander n. sp. a generalist. These parasite species show morphological similarities to species found in the Lower Guinea and Zambezi ichthyofaunal provinces, which might be explained by past river capture events between river systems of the Congo Province and both these regions.ConclusionsSerranochromis cf. macrocephalus and Orthochromis sp. ‘Lomami’ can harbour respectively three and two species of Cichlidogyrus, all described in this study. Tilapia sparrmanii can harbour seven species, of which three are described in the present study. These results highlight the species diversity of this parasite genus in the Congo Basin.

The Scaly-foot Snail genome and implications for the origins of biomineralised armour

The Scaly-foot Snail, Chrysomallon squamiferum, presents a combination of biomineralised features, reminiscent of enigmatic early fossil taxa with complex shells and sclerites such as sachtids, but in a recently-diverged living species which even has iron-infused hard parts. Thus the Scaly-foot Snail is an ideal model to study the genomic mechanisms underlying the evolutionary diversification of biomineralised armour. Here, we present a high-quality whole-genome assembly and tissue-specific transcriptomic data, and show that scale and shell formation in the Scaly-foot Snail employ independent subsets of 25 highly-expressed transcription factors. Comparisons with other lophotrochozoan genomes imply that this biomineralisation toolkit is ancient, though expression patterns differ across major lineages. We suggest that the ability of lophotrochozoan lineages to generate a wide range of hard parts, exemplified by the remarkable morphological disparity in Mollusca, draws on a capacity for dynamic modification of the expression and positioning of toolkit elements across the genome.

Length based assessment of spawning potential ratio in data-poor fisheries for blue swimming crab (Portunus spp.) in Sri Lanka and Indonesia: Implications for sustainable management

Quantitative assessment and management of small-scale fisheries is a persistent problem for fisheries. Crustaceans are particularly challenging for conventional techniques because their lack of permanent hard body parts makes ageing difficult. While a growing body of literature is aimed at developing alternative approaches to small-scale fisheries assessment there are concerns about the indiscriminate application of generic methodologies and the need to address the specific circumstances of fisheries. The length-based assessment of spawning potential ratio (LBSPR) is appealing because it has simple data requirements, a well-developed theoretical foundation, and estimates Spawning Potential Ratio (SPR) an internationally recognized indicator of stock status. With the aim of establishing basic standards and providing structured discussion of the issues raised by its application, this study documents its application to the regionally important blue swimming crab (BSC) (Portunus spp.) fisheries, in Sri Lanka and Indonesia. Our study demonstrates the methods technical feasibility and cost-effectiveness for small-scale BSC fisheries and by extension other small-scale fisheries. In Sri Lanka and Indonesia, these LBSPR assessments are successfully informing discussions about sustainability; focusing discussion on managing size selectivity, one of the few management controls available to fisheries managers in many small-scale fisheries. In Indonesia BSC are first caught at around the size of maturity by trawling and with baited traps without escape gaps, reducing SPR to unsustainable levels. Despite similarly high fishing pressure, in Sri Lanka the larger size of first capture with bottom set nets preserves a sustainable level of SPR. Supported by these assessments, in 2018, that fishery attained a provisional sustainability rating from Seafood Watch. We suggest how LBSPR assessment might be used to adaptively manage size selectivity within the harvest strategy being developed in Indonesia. It is hoped this documentation of the methodology will assist other small-scale fisheries to use this technique similarly.