Floor heave in the west wing track haulage roadway of the Tingnan Coal Mine: Mechanism and control

Floor heave of a roadway is a dynamic phenomenon that often happens in the roadways of coal mines. It seriously affects safe production in the coal mine. Floor heave has long been one of the most difficult problems to be resolved during coal mining. An analysis of floor heave in the soft rock surrounding the roadway, and the factors influencing it, allowed the deformation mechanism in the west wing double track haulage roadway of the Tingnan Coal Mine to be deduced. Three types of floor heave are observed there: intumescent floor heave, extrusion and mobility floor heave, and compound floor heave. Control measures are proposed that have been adopted during a recent repair engineering project. Control of the floor heave in the west wing track haulage roadway was demonstrated. The reliability and rationality of a combined support technology including floor anchors, an inverted arch, and anchoring of both sides was verified by mine pressure data and the field observations. Waterproofing measures were also under-taken to assist in the control of floor heave.

Risk assessment of floor water inrush in coal mines based on MFIM-TOPSIS variable weight model

Floor water inrush is one of the main types of coal mine water hazards.With the development of deep mining,the prediction and evaluation of floor water inrush is particularly significant.This paper proposes a variable weight model,which combines a multi-factor interaction matrix(MFIM)and the technique for order performance by similarity to ideal solution(TOPSIS)to implement the risk assessment of floor water inrush in coal mines.Based on the MFIM,the interaction between seven evaluation indices,including the confined water pressure,water supply condition and aquifer water yield property,floor aquifuge thickness,fault water transmitting ability,fracture development degree,mining depth and thickness and their influence on floor water inrush were considered.After calculating the constant weights,the active degree evaluation was used to assign a variable weight to the indices.The values of the middle layer and final risk level were obtained by TOPSIS.The presented model was successfully applied in the 9901 working face in the Taoyang Mine and four additional coal mines and the results were highly consistent with the engineering situations.Compared with the existing nonlinear evaluation methods,the proposed model had advantages in terms of the weighting,principle explanation,and algorithm structure.

Application of the coal mine floor rating(CMFR)to assess the floor stability in a Central Appalachian Coal Mine

Estimating the overall floor stability in a coal mine using deterministic methods which require complex engineering properties of floor strata is desirable,but generally it is impractical due to the difficulty of gathering essential input data.However,applying a quantitative methodology to describe floor quality with a single number provides a practical estimate for preliminary assessment of floor stability.The coal mine floor rating(CMFR)system,developed by the University of New South Wales(UNSW),is a rockmass classification system that provides an indicator for the competence of floor strata.The most significant components of the CMFR are uniaxial compressive strength and discontinuity intensity of floor strata.In addition to the competence of the floor,depth of cover and stress notch angle are input parameters used to assess the preliminary floor stability.In this study,CMFR methodology was applied to a Central Appalachian Coal Mine that intermittently experienced floor heave.Exploratory drill core data,overburden maps,and mine plans were utilized for the study.Additionally,qualitative data(failure/non-failure)on floor conditions of the mine entries near the core holes was collected and analyzed so that the floor quality and its relation to entry stability could be estimated by statistical methods.It was found that the current CMFR classification system is not directly applicable in assessing the floor stability of the Central Appalachian Coal Mine.In order to extend the applicability of the CMFR classification system,the methodology was modified.A calculation procedure of one of the CMFR classification system’s components,the horizontal stress rating(HSR),was changed and new parameters were added to the HSR.

Nutrients in litterfall,forest floor and mineral soils in two adjacent forest ecosystems in Greece

The fluxes of masses and the nutrients Ca,Mg,K,N,P and S were determined in the litterfall of two adjacent forest ecosystems of Hungarian oak(Quercus frainetto L.)and European beech(Fagus sylvatica L.)in a mountainous area of northeastern Greece in 2010–2015.The foliar litterfall for both species reached about 70%of the total litterfall,and was significantly higher from the other two fractions(woody and rest litterfall).The fluxes of masses and nutrients were compared between ecosystems for each fraction separately.Only one significant statistical difference was found,that of K in the woody litterfall.In addition,the stocks of masses and nutrients were calculated in the forest floors and mineral soils of the two ecosystems.Likewise,the stocks of nutrients in the forest floors and mineral soils were compared between ecosystems.In the L horizon of the forest floors,statistical differences,as a result of species effect,were found for the stocks of Ca and N.In the FH horizons,the masses and all the nutrient stocks differed significantly,as the beech plot had much higher quantities of organic matter and nutrients.These higher quantities were probably due to low soil temperatures(microclimate)and high acidity in the beech plot(species effect)that slowed down decomposition.In the mineral soils,the propagation of random error derived from random errors of the individual soil layers was an important factor in the statistical comparisons.Because of the soil acidity in the beech plot,the stocks of exchangeable base cations were significantly higher in the oak plot,whereas the other nutrient stocks did not differ.

Analysis of roof and pillar failure associated with weak floor at a limestone mine

A limestone mine in Ohio has had instability problems that have led to massive roof falls extending to the surface. This study focuses on the role that weak, moisture-sensitive floor has in the instability issues.Previous NIOSH research related to this subject did not include analysis for weak floor or weak bands and recommended that when such issues arise they should be investigated further using a more advanced analysis. Therefore, to further investigate the observed instability occurring on a large scale at the Ohio mine, FLAC3 D numerical models were employed to demonstrate the effect that a weak floor has on roof and pillar stability. This case study will provide important information to limestone mine operators regarding the impact of weak floor causing the potential for roof collapse, pillar failure, and subsequent subsidence of the ground surface.

Mitigation of floor heave in West Kentucky Coal Mine

A West Kentucky mine operation in No. 11 seam encountered floor heave, due to the localized increase in the thickness of the fireclay mine floor. Floor heave has overridden seals installed in two mined out panels. The third seal's location was planned for isolating that area from the Mains. A plan of support has been developed to prevent repetition of the floor heave and related problems outby the seals. The applied ground control measures were successful. An attempt of a 3D numerical modeling was made; thus, it would match the observed behavior of the mine floor and could be used as a design tool in similar conditions. The paper describes sequence of events, an applied mitigation ground control system, and the first stage of numerical modeling.

Water abundance of mine floor limestone by simulation experiment

The water abundance of mine floor limestone needs to be solved urgently as the average depth of coal mining in China has increased gradually. A method is presented to discuss water abundance with the numerical and physical layered geoelectrical model being established in the half-space, full-space and full-space with tunnel, respectively. The parameters of water abundance are changed in this study, which includes water quantity, water content and volume of abnormity of water-containing abnormity. Results indicate that the different work fields have different macroscopic influences on the apparent resistivity,and the water abundance parameters of water-containing abnormity have quantitative relationship with the apparent resistivity mean in abnormal regions(three-dimensional space region). The quantitative relationships are shown as following: firstly, the amount of water injection has negative linear correlation with the apparent resistivity mean; secondly, when abnormity is unsaturated, there is a negative power function relationship between water content and apparent resistivity mean; thirdly, the volume of abnormity and apparent resistivity mean behave as a decreasing power function law.

Consultation system of forecasting the mine floor flood

In this paper, on the basis of the analysis of the current situation of the mine floor flood and the consultation system study, the overall design and structure, specially, the mechanism of many kinds of method for making a strategic decision and reasoning of the system of prevention and control of mine floor flood are introduced. The applied examples are given at last.

Mine disaster survivor’s pelvic floor hernia treated with laparoscopic surgery and a perineal approach:A case report

BACKGROUND A pelvic floor hernia is defined as a pelvic floor defect through which the intraabdominal viscera may protrude.It is an infrequent complication following abdominoperineal surgeries.This type of hernia requires surgical repair by conventional or reconstructive techniques.The main treatments could be transabdominal,transperineal or a combination.CASE SUMMARY In this article,we present the case of a recurrent perineal incisional hernia,postresection of the left side of the pelvis,testis and lower limbs resulting from a mine disaster 18 years ago.Combined laparoscopic surgery with a perineal approach was performed.The pelvic floor defect was repaired by a biological mesh and one pedicle skin flap.No signs of recurrence were indicated during the 2 years of follow-up.CONCLUSION The combination of laparoscopic surgery with a perineal approach was effective.The use of the biological mesh and pedicle skin flap to restructure the pelvic floor was effective.

Effect of artesian water on the mine floor water inrush and significance of similitude simulation to it

According to the in situ statistics data, indoor rock hydraulic fracturing experiments and numerical simulation results, the role of artesian water quantity was analyzed, emphasis was put on the analysis of the damage mechanics of artesian water to rocks under the floor and the softening, solution and scouring action of artesian water were also researched. At the end of the paper, practical significance of similar material simulation to the influence of artesian water on water inrush under the floor was discussed and hoped to provide references to the artesian water hydraulics simulation experiment devices design and test based on the indoor similar material simulation platform.

Restraint effect of partition wall on the tunnel floor heave in layered rock mass

The presence of horizontal layered rocks in tunnel engineering significantly impacts the stability and strength of the surrounding rock mass,leading to floor heave in the tunnel.This study focused on preparing layered specimens of rock-like material with varying thickness to investigate the failure behaviors of tunnel floors.The results indicate that thin-layered rock mass exhibits weak interlayer bonding,causing rock layers near the surface to buckle and break upwards when subjected to horizontal squeezing.With an increase in the layer thickness,a transition in failure mode occurs from upward buckling to shear failure along the plane,leading to a noticeable reduction in floor heave deformation.The primary cause of significant deformation in floor heave is upward buckling failure.To address this issue,the study proposes the installation of a partition wall in the middle of the floor to mitigate heave deformation of the rock layers.The results demonstrate that the partition wall has a considerable stabilizing effect on the floor,reducing the zone of buckling failure and minimizing floor heave deformation.It is crucial for the partition wall to be sufficiently high to prevent buckling failure and ensure stability.Through simulation calculations on an engineering example,it is confirmed that implementing a partition wall can effectively reduce floor heave and enhance the stability of tunnel floor.

Curative effect of hydrogen peroxide combined with silver ion disinfection on pelvic floor dysfunction

BACKGROUND Pelvic floor dysfunction(PFD)is related to muscle fiber tearing during childbirth,negatively impacting postpartum quality of life of parturient.Appropriate and effective intervention is necessary to promote PFD recovery.AIM To analyze the use of hydrogen peroxide and silver ion disinfection for vaginal electrodes in conjunction with comprehensive rehabilitation therapy for postpartum women with PFD.METHODS A total of 59 women with PFD who were admitted to the hospital from May 2019 to July 2022 were divided into two groups:Control group(n=27)received comprehensive rehabilitation therapy and observation group(n=32)received intervention with pelvic floor biostimulation feedback instrument in addition to comprehensive rehabilitation therapy.The vaginal electrodes were disinfected with hydrogen peroxide and silver ion before treatment.Intervention for both groups was started 6 weeks postpartum,and rehabilitation lasted for 3 months.Pelvic floor muscle voltage,pelvic floor muscle strength,vaginal muscle voltage,vaginal muscle tone,pelvic floor function,quality of life,and incidence of postpartum PFD were compared between the two groups.RESULTS Before comprehensive rehabilitation treatment,basic data and pelvic floor function were not significantly different between the two groups.After treatment,the observation group showed significant improvements in the maximum voltage and average voltage of pelvic floor muscles,contraction time of type I and type II fibers,pelvic floor muscle strength,vaginal muscle tone,vaginal muscle voltage,and quality of life(GQOLI-74 reports),compared with the control group.The observation group had lower scores on the pelvic floor distress inventory(PFDI-20)and a lower incidence of postpartum PFD,indicating the effectiveness of the pelvic floor biostimulation feedback instrument in promoting the recovery of maternal pelvic floor function.CONCLUSION The combination of the pelvic floor biostimulation feedback instrument and comprehensive rehabilitation nursing can improve pelvic floor muscle strength,promote the recovery of vaginal muscle tone,and improve pelvic floor function and quality of life.The use of hydrogen peroxide and silver ion disinfectant demonstrated favorable antibacterial efficacy and is worthy of clinical application.

Botulinum toxin type A injection combined with biofeedback in the treatment of spastic pelvic floor syndrome

BACKGROUND Spastic pelvic floor syndrome(SPFS)is a refractory pelvic floor disease characterized by abnormal(uncoordinated)contractions of the external anal sphincter and puborectalis muscle during defecation,resulting in rectal emptation and obstructive constipation.The clinical manifestations of SPFS are mainly characterized by difficult defecation,often accompanied by a sense of anal blockage and drooping.Manual defecation is usually needed during defecation.From physical examination,it is commonly observed that the patient's anal muscle tension is high,and it is difficult or even impossible to enter with his fingers.AIM To investigate the characteristics of anorectal pressure and botulinum toxin A injection combined with biofeedback in treating pelvic floor muscle spasm syndrome.METHODS Retrospective analysis of 50 patients diagnosed with pelvic floor spasm syndrome.All patients underwent pelvic floor surface electromyography assessment,anorectal dynamics examination,botulinum toxin type A injection 100 U intramuscular injection,and two cycles of biofeedback therapy.RESULTS After the botulinum toxin A injection combined with two cycles of biofeedback therapy,the patient's postoperative resting and systolic blood pressure were significantly lower than before surgery(P<0.05).Moreover,the electromyography index of the patients in the resting stage and post-resting stages was significantly lower than before surgery(P<0.05).CONCLUSION Botulinum toxin A injection combined with biofeedback can significantly reduce pelvic floor muscle tension in treating pelvic floor muscle spasm syndrome.Anorectal manometry is an effective method to evaluate the efficacy of treatment objectively.However,randomized controlled trials are needed.

Basic Characteristics of an Appropriate Waste Fillers for Solvent Free and Water-Borne Industrial Polymer Floors and Their Utilization

Recently the manufacture of epoxy coating and flooring materials begun to be under strong pressure to use more environmentally friendly raw materials in its composition.First tendency to reduce of solvents and diluents contained in the materials appeared at the end of 90´s.This situation was supported by the Council of Europe in 2004 to reduce VOC emissions to zero till 2020.Solvent materials were thus largely replaced by solvent free materials from which the volatile substances are not released into the air.But pressure continued to increase,and over the past decade began to take centre stage water-based epoxy.On the Czech market solvent based material is still occasionally used,but predominant are solvent free materials.There are no commonly used materials containing wastes as fillers in new water-borne and solvent-free epoxy materials.Characteristics identification of the waste material as a potential filler is a set of properties that determine the limits of secondary raw materials or waste as a filler.This paper describes the basic characteristics which must be selected to meet the requirements,to affect negatively the workability,sedimentation,properties and behavior of the final floor system.Some materials must comply with special requirements,such as resistance to chemicals,etc.Next part of paper talks about utilization of polymer floors and their mechanical properties.

Further Analysis of Machine Tool Dimensional Accuracy and Thermal Stability under Varying Floor Temperature

Machining is as old as humanity, and changes in temperature in both the machine’s internal and external environments can be of great concern as they affect the machine’s thermal stability and, thus, the machine’s dimensional accuracy. This paper is a continuation of our earlier work, which aimed to analyze the effect of the internal temperature of a machine tool as the machine is put into operation and vary the external temperature, the machine floor temperature. Some experiments are carried out under controlled conditions to study how machine tool components get heated up and how this heating up affects the machine’s accuracy due to thermally induced deviations. Additionally, another angle is added by varying the machine floor temperature. The parameters mentioned above are explored in line with the overall thermal stability of the machine tool and its dimensional accuracy. A Robodrill CNC machine tool is used. The CNC was first soaked with thermal energy by gradually raising the machine floor temperature to a certain level before putting the machine in operation. The machine was monitored, and analytical methods were deplored to evaluate thermal stability. Secondly, the machine was run idle for some time under raised floor temperature before it was put into operation. Data was also collected and analyzed. It is observed that machine thermal stability can be achieved in several ways depending on how the above parameters are joggled. This paper, in conclusion, reinforces the idea of machine tool warm-up process in conjunction with a carefully analyzed and established machine floor temperature variation for the approximation of the machine tool’s thermally stability to map the long-time behavior of the machine tool.

Turbulence regime near the forest floor of a mixed broad leaved/Korean pine forest in Changbai Mountains

The measurement and observation for this study were carried out by using a three-dimensional (u, v, w) Sonic anemometer (IAP-SA 485), at Forest Ecosystem Opened Research Station of Changbai Mountains (12828扙 and 4224?N, Jilin Province, P. R. China) in August 2001. The basic characteristics of turbulence, such as turbulence intensity, atmospheric stability, time scales, and convection state, near the forest floor were analyzed. It is concluded that the airflow near forest floor is characterized by high intermittence and asymmetry, and the active and upward movement takes the leading position. Near forest floor, the vertical turbulence is retained and its time scale and length scale are much less than that of u, v components. The eddy near forest floor shows a flat structure and look like a ’Disk’. Buoyancy plays a leading role in the generation and maintenance of local turbulence

A HOLONIC FRAMEWORK OF RECONFIGURABLE SHOP FLOOR CONTROL SYSTEMS IN AUTOMATED MANUFACTURING SYSTEMS

The agility and the flexibility of the current shop floor control systems have been limited so far, owing to the lack of structural flexibility and agility in its control software layer. Most of them are based on traditional hierarchical architecture and the top down approach and depend structurally on their specific configuration and job scheduling. Not only can they hardly satisfactorily adapt to these increasing changes and disturbances, but also make the redevelopment and maintenance of shop floor control system (SFCS) to need high cost and much time. And SFCS based on the heterarchical architecture don′t provide a predictable and high performance system, especially not in the heterogeneous environments, where the resources are scarce and the current decisions have serious repercussions on the future performances. For this reason, the heterarchical control is hardly applied in industry. Obviously, it is necessary to develop a new structural framework of reconfigurable SFCS to improve their agility, flexibility and maintainability. This paper presents a holonic framework of reconfigurable SFCS based on holonic manufacturing concepts. The framework is composed of resource holons, product holons and other staff holons. The model of each holon and the co operative mechanisms of holons are described. To verify the proposed approach experimentally, a prototype reconfigurable SFCS for a flexible manufacturing shop floor producing discrete parts is implemented.

Experimental investigation on heat transfer characteristics of a new radiant floor system with phase change material

In order to improve the heat transfer characteristics of the traditional phase change material（PCM） floor, a new double-layer radiant floor system with PCM is proposed, which can store thermal or cold energy in the off-peak period and use them in the peak period. An experimental setup was developed to study the heat transfer characteristics of the new system under both cooling and heating modes. The experimental results show that the double-layer radiant floor system with PCM can meet both the cold and thermal requirements of users. Moreover, with the same duration of the thermal energy storage process, the increase of water temperature supplied to the system can improve the heat transfer characteristics of the system but lead to the discomfort of users. On the other hand, if the air temperature at the end of the thermal energy storage process is the same under different conditions, the increase of supplied water temperature will decrease the thermal energy storage time and ensure the comfort of users.

INTEGRATION OF GENERIC SHOP FLOOR CONTROL

Based on the discussion of functions, components, control structure and network computing architecture of generic shop floor control (GSFC) in computer integrated manufacturing system (CIMS), the internal integration between components of GSFC and the external integration between GSFC and the other components of CIMS are studied. The integration models on the aspects of function, information, processing and interface are put forward. The integration models and the methods are implemented and applied in CIMS projects successfully.

Experimental study of low-temperature electrical radiant floor heating system

To evaluate the thermal performance of a low-temperature electrical radiant floor heating system,an experimental facility equipped with a constant temperature chamber and different specimen floors is designed and built.The heating cable is installed in the floor slab with a unit-rated power of 30 W/m.Twenty-four different schemes are worked out and tested,which include three kinds of composite floor structures and eight kinds of cable distances.The cable distances are 30,40,50,60,80,100,130,150 mm.The main affective factors of the thermal performance and their influencing regularity are discussed.The experimental results show that the system has good stability and reliability,and the ratio of the radiation heat-transfer rate to the gross heat-transfer rate is greater than 50%.When the floor structure and the cable distance are fixed,the gross heat-transfer rate of the upper floor surface has a maximum value at an optimal cable distance.Under the experimental conditions in this paper,the optimal cable distance is 50 mm.