Modeling of Failure Prediction Bayesian Network with Divide-and-Conquer Principle

For system failure prediction, automatically modeling from historical failure dataset is one of the challenges in practical engineering fields. In this paper, an effective algorithm is proposed to build the failure prediction Bayesian network (FPBN) model with data mining technology. First, the conception of FPBN is introduced to describe the state of components and system and the cause-effect relationships among them. The types of network nodes, the directions of network edges, and the conditional probability distributions (CPDs) of nodes in FPBN are discussed in detail. According to the characteristics of nodes and edges in FPBN, a divide-and-conquer principle based algorithm (FPBN-DC) is introduced to build the best FPBN network structures of different types of nodes separately. Then, the CPDs of nodes in FPBN are calculated by the maximum likelihood estimation method based on the built network. Finally, a simulation study of a helicopter convertor model is carried out to demonstrate the application of FPBN-DC. According to the simulations results, the FPBN-DC algorithm can get better fitness value with the lower number of iterations, which verified its effectiveness and efficiency compared with traditional algorithm

Reservoir properties and genesis of tight sandstones—A case study from the Gaotaizi oil layer in the Qijia area, Songliao basin

The primary focus of oil and gas exploration for tight sandstone reservoirs is on a quantitative characterization of reservoir properties. This paper uses the tight sandstone reservoir developed in the Gaotaizi oil layer in the Qijia area of the Songliao Basin as an example. The petrology, physical properties, pore–throat characteristics, and the genesis of the densification of the oil-bearing sandstones are elucidated using casting thin-sections, scanning electron microscopy, 3D computerized tomography (CT), and petrophysical experimental techniques. The results show that the Gaotaizi oil layer is mainly composed of clastic rocks and contains small amounts of shell limestone. The clastic rocks are mainly lithic feldspar sandstone and feldspar lithic sandstone, while residual intergranular pores, intergranular dissolved pores, intragranular dissolved pores, intragranular pores and intercrystalline pores constitute the different pore types. Mercury intrusion and 3D computerized tomography analysis showed that micro-nano pores account for 53% of the total pores present. The pore–throat coordination number is distributed between 1 and 4, with an average of 1.8. The pores and throats in the Gaotaizi reservoir have poor connectivity. The porosity distribution of the Gaotaizi oil layer is 1.4%–22.5%, with an average of 9.5%, while the permeability distribution ranges from 0.01 to 27.10 mD, with an average of 0.41 mD. It is an ultra-low porosity and ultra-low permeability tight reservoir. The Gaotaizi oil layer is divided into three types of reservoirs through a systematic study of its pore developmental characteristics. Diagenetic processes like compaction and cementation result in a reduction in porosity and permeability. Compaction, calcite and siliceous cementation, and illite packing are primarily responsible for reservoir densification

Cutaneous horn masquerading as a seborrheic keratosis

Purpose: To report a case of seborrheic keratosis of the inner canthus presenting as cutaneous horn. Observation: A 67-year-old Asian male presented with a rod-shaped, pedunculated mass on his inner canthus. The mass grew rapidly and within 2 months measured 3.0 cm in length and 0.5 cm in diameter. It was completely excised and submitted for microscopic examination. The specimen consisted of a proliferation of basaloid cells arranged in a papillary pattern and associated with significant hyperkeratosis and parakeratosis of the overlying squamous epithelium. The pathological diagnosis was reported as seborrheic keratosis from the skin of the inner canthus. Conclusions and importance: Seborrheic keratosis can develop into a rapidly expanding lesion such as a cutaneous horn and can be found in unusual locations. To our knowledge, this is the first report of a seborrheic keratosis from the skin of the inner canthus

Diagenesis of tight sandstone and its influence on reservoir properties: A case study of Fuyu reservoirs in Songliao Basin, China

Diagenesis is the primary cause of the densification of the Fuyu reservoir in Sanzhao sag, Songliao Basin. In this paper, the types of diagenesis, the influence of diagenesis on reservoir physical properties and the formation reasons of tight reservoir in Fuyu oil layer were studied by means of ordinary thin sections, casting thin sections, cathodoluminescence and scanning electron microscope. Results show that the diagenesis of the Fuyu reservoir in Sanzhao sag mainly includes compaction, cementation, metasomatism, and dissolution. Compaction and cementation are the main reasons for the compactness of the Fuyu reservoir in Sanzhao sag. The compactness causes also vary in different parts of the Fuyu reservoir. At the bottom of the Fuyu oil layer, the porosity reduction rate of early calcite cementation is 77%, and that of compaction is 9.23%. Cementation is the primary cause of reservoir compactness, and compaction is the secondary factor. In the middle and upper sections of the Fuyu reservoir, the porosity reduction rate of compaction is 50%, and that of cementation is 32.31%. Compaction is the main reason causing reservoir compactness, and cementation is the secondary factor. This work extensively analyzes the diagenesis characteristics of the Fuyu reservoir and its influence on the reservoir physical properties, providing a scientific basis for the study of the reservoir physical properties and the prediction of high-quality reservoirs

Effects of Dietary Alfalfa Meal Supplementation on the Growth Performance, Nutrient Apparent Digestibility, Serum Parameters, and Intestinal Microbiota of Raccoon Dogs (<i>Nyctereutes procyonoides</i>)

The raccoon dog (Nyctereutes procyonoides) is a typical omnivore possessing wide dietary adaptability and tolerance to rough feeding, which may be attributed to its intestinal microbiota. The study aimed to investigate the effect of dietary alfalfa meal levels on the growth performance, nutrient apparent digestibility, serum parameters, and intestinal microbiota of raccoon dogs. Sixty raccoon dogs were randomly divided into four dietary treatments containing 0% (AM0), 5% (AM5), 10% (AM10), and 15% (AM15) alfalfa meal for a 60-day experiment. The results showed that compared to raccoon dogs fed the AM0 diet, those fed the AM5 and AM10 diets had no significant difference in growth performance, while those fed the AM15 diet experienced a significant decrease. Raccoon dogs fed the AM5 diet had no significant effect on the nutrient apparent digestibility. Dietary supplementation with alfalfa meal significantly decreased serum urea levels and increased the antioxidant capacity of raccoon dogs. The intestinal microbiome analysis showed that the richness and diversity of colonic microbiota significantly increased in the AM15 group. With the increase in dietary alfalfa meal levels, the relative abundance of fiber-degrading bacteria in the colon of raccoon dogs, such as Treponema, Phascolarctobacterium, and Christensenellaceae R-7 group, increased. However, the relative abundance of pathogenic bacteria, including Anaerobiospirillum, decreased. In conclusion, the inclusion of 5% alfalfa meal in the raccoon dogs’ diet had no effect on growth performance, but it exhibited the potential to improve serum antioxidant capacity and intestinal microbiota. This indicates that raccoon dogs have a certain tolerance to the addition of alfalfa meal in their diet