Effect of temperature on dielectric property and microwave heating behavior of low grade Panzhihua ilmenite ore

The permittivity of low grade Panzhuhua ilmenite ore at 2.45 GHz in the temperatures from 20 ℃ up to 100 ℃ was measured using the technology of open-ended coaxial sensor combined with theoretical computation. The results show that both the real （ε′） and imaginary （ε′） part of complex permittivity （ε′-jε′） of the ilmenite significantly increase with temperature. The loss tangent （tanδ） is a quadratic function of temperature, and the penetration depth of ilmenite decreases with temperature increase from 20 ℃to 100 ℃ The increase of the sample temperature under microwave radiation displays a nonlinear relationship between the temperature （T） and microwave heating time （t）. The positive feedback interaction between complex permittivity and sample temperature amplifies the interaction between ilmenite and the microwave radiation. The optimum dimensions for uniform heat deposition vary from 10 cm to 5 cm （about two power penetration depths） in a sample being irradiated from both sides in a 2.45 GHz microwave field when temperature increases from room temperature to 100 ℃

Recovery of vanadium and carbon from low-grade stone coal by flotation

Flotation technology of high-carbon stone coal bearing vanadium was investigated based on mineralogical study. Carbon and vanadium flotation circuits were included in the flotation process for carbon and vanadium mineral concentrates. Carbon and vanadium minerals were efficiently separated via regrinding process in the carbon flotation circuit. The results show that the grade and recovery of V2O5 in flotation concentrate are 1.32% and 88.38%, respectively, and the tailings yield is 38.36%. Meanwhile, the grade and recovery of the carbon mineral are 30.08% and 75.10%, respectively, which may be utilized as the fossil fuels directly. The leaching rates of the flotation products are as high as 85%. The results demonstrate that there is no direct adverse effect of flotation process on vanadium leaching. This technology could potentially reduce cost and increase the treatment capacity of vanadium extraction and provide reference to stone coal flotation technology.

Synthesis of nickel ferrite precursors from low grade nickel matte

Fine nickel ferrite precursors NiFe2（C204）3·6H2O were obtained via co-precipitation method with low grade nickel matte as the raw material. Thermodynamic analysis of NiClz-FeC12-（NH4）2C204-H20 system for precipitation identified that the theoretical optimum co-precipitation pH value is 2, and C2O2 has strong complexation with Ni2＋ and Fe2＋ ions. Based on these theoretical considerations, the effects of parameters on the precipitation rates and precursors size were investigated systematically. The results show that the optimum co-precipitation conditions are pH=2, temperature 45 ℃, 1.2 times theoretical amount of （NH4）2C204 dosage and 3% PEG400 addition. Under these conditions, the precipitation rates of Ni2＋ and Fe2＋ are both over 99.8%, with the precursors size of 1-2 urn. Furthermore, X-ray diffraction （XRD） and thermogravimetry-differential thermal analysis （TG-DTA） demonstrate that the precursors are single-phase solid solution, wherein the nickel/iron atoms are replaced by the iron/nickel atoms reciprocally.

Multi-effect distillation system for seawater desalination driven by tidal energy and low grade energy

A multi-effect distillation technology for seawater desalination driven by tidal energy and low grade energy is presented.In the system,tidal energy is utilized to supply power instead of coventional electric pumps during the operation,resulting in the decrease of dependence on steady electric power supply and a reduction in the running costs.According to the technological principle,a testing unit is designed and built.The effects of the feed seawater temperature and the heat source temperature on the unit performance are tested and analyzed.The experimental results show that the fresh water output is 27 kg/h when the heating water temperature is 65 ℃ and the absolute pressure is 25 kPa.The experimental and theoretical analysis results indicate that the appropriate heating water temperature is a key factor in ensuring the steady operation of the system.

Primary ovarian cancer combined with primary fallopian tube cancer:A case report

BACKGROUND Low grade serous carcinoma of the ovary(LGSOC)is a rare type of epithelial ovarian cancer with a low incidence rate.The origin of ovarian cancer has always been a hot topic in gynecological oncology research,and some scholars believe that the origin of ovarian malignant tumors is the fallopian tubes.Primary fallopian tube cancer is the lowest incidence of malignant tumors in the female reproductive system.There are only a few reports in the literature,but the mortality rate is very high.But in clinical practice,fallopian tube cancer is very common,but in most cases,it is classified as ovarian cancer.CASE SUMMARY We report a 54 years old postmenopausal woman who was hospitalized with a lower abdominal mass and underwent surgical treatment.The final pathological confirmation was low-grade serous carcinoma of the right ovary and low-grade serous carcinoma of the left fallopian tube.No special treatment was performed after the surgery,and the patient was instructed to undergo regular follow-up without any signs of disease progression.CONCLUSION The prognosis of LGSOC is relatively good,over 80%of patients still experience disease recurrence.

Dissolution kinetics of low grade complex copper ore in ammonia-ammonium chloride solution

The leaching kinetics of Tang-dan refractory low grade complex copper ore was investigated in ammonia-ammonium chloride solution.The concentration of ammonia and ammonium chloride,the ore particle size,the solid-to-liquid ratio and the temperature were chosen as parameters in the experiments.The results show that temperature,concentration of ammonia and ammonium chloride have favorable influence on the leaching rate of copper oxide ores.But,leaching rate decreases with increasing particle size and solid-to-liquid ratio.The leaching process is controlled by the diffusion of the lixiviant and the activation energy is determined to be 23.279 kJ/mol.An equation was also proposed to describe the leaching kinetics.

Relationship between process mineralogical characterization and beneficiability of low-grade laterite nickel ore

Process mineralogy of low-grade laterite nickel ore in Indonesia was systematically characterized and the beneficiation process of mineral components such as limonite,serpentine and chromite was studied on the basis of process mineralogy.The results show that the low-grade laterite nickel ore is a typical weathering sedimentary metamorphic oxidized ore,with the main valuable elements of Ni,Co and Cr and the main mineral components of limonite,serpentine,chromite,etc.There is no independent carrier mineral of Ni and Co in the raw ore,and the occurrence states of Ni and Co are relatively dispersed.For the limonite in laterite nickel mine,the nickel bearing magnetite concentrate with nickel grade of 1.98%and recovery rate of 88.42%can be obtained by reduction roasting magnetic separation process.For the serpentine in laterite nickel mine,the cobalt bearing concentrate with Co grade of 0.17%and recovery rate of 23.17%can be obtained by positive and reverse flotation process.A chromium concentrate containing 35.17%Cr_(2)O_(3) and a recovery of 33.42%can be obtained by using the combined process of coarse and fine classification and gravity and magnetic.

Effect of copper slag recovery on hydrometallurgical cut-off grades considering environmental aspects

Determining the hydrometallurgical cut-off grades specifies the destination of low grade materials and this is subjected to more benefits in mining. Copper production rate is considered as one of the fundamental issues in hydrometallurgical cut-off grades determination. Slags are remarked as one of the main sources of copper. It is not only regarded as a waste but also identified as another resource extracting base metals. Slags are characterized by copper high grade. Thus, slag copper recovery can be led to different cut-off grades and net present value(NPV). The current research scrutinizes the effect of slag recovery by both flotation and hydrometallurgical methods on the hydrometallurgical cut-off grades. For this purpose, the optimum cut-off grade algorithms of hydrometallurgical methods are developed by considering associated environmental parameters, incomes and also the costs. Then, their optimum amounts are calculated with NPV maximization as an objective function. The results indicate that considering slag copper recovery in the hydrometallurgical cut-off grade algorithms reduces the environmental costs caused by slag dumping and leads to more NPV by 9%.

Flotation technology of refractory low-grade molybdenum ore

Because of the low grade, high oxidation rate and the accumulation of little associated metal sulfide ore in the molybdenum concentrate during flotation, the Qingyang molybdenum ore is difficult to beneficiate. The experimental studies of grinding fineness, the amount of roughing modifier, depressant and collector were completed. In the cleaning process, the contrast experiments of one regrinding, the regrinding and scrubbing, two-stage regrinding was carried. The result shows that the grade of molybdenum ore concentrate is 45.31%, the recovery is 65.98% and the rich ore ratio reaches 20.59% by the regrinding and scrubbing seven cleaning, the regrinding of concentrations from middling of molybdenum-sulfur separation. The regularly-concentrated material from the apparatus was as the middling products. Hence, ideal beneficiation index can be obtained with a rational mineral processing, which offers new beneficiating technology for the refractory low-grade molybdenum ore in China.

Effect of technological factors on bacterial leaching of low-grade Ni-Cu sulfide ore

The bioleaching of a low grade Ni Cu sulfide ore from Jinchuan Mine with Thiobacillus ferrooxidans (TF5) and Thiobacillus thiooxidans (TT) was investigated. The effect of pH, the initial cell numbers of bacteria, the pulp density and the ratio of TF5 and TT on leaching was described, and the favorable bioleaching conditions for the ore were experimentally confirmed. The aeration leaching, agitation leaching with air bubbling, and column leaching were respectively tested. The highest recovery was achieved in the aeration leaching. After leaching for 20?d with pulp density of 15%, the extractions of Ni, Cu and Co were respectively 95.4%, 48.6% and 82.6%.

Enhanced copper recovery from low grade copper sulfide ores through bioleaching using residues produced by fermentation of agricultural wastes

Effects of residues produced by agricultural wastes fermentation(AWF)on low grade copper sulfide ores bioleaching,copper recovery,and microbial community were investigated.The results indicated that adding appropriate bulk of AWF made contributions to low grade copper sulfide ores bioleaching,which may be mainly realized through reducing the passivation layer formed by Fe3+hydrolysis.Improved copper recovery(78.35%)and bacteria concentration(9.56×10^(7)cells·mL^(−1))were yielded in the presence of 5 g·L^(−1)AWF.The result of 16S rDNA analysis demonstrated that microbial community was differentiated by adding AWF.Bacteria proportion,such as Acidithiobacillus ferrooxidans,Moraxella osloensis,and Lactobacillus acetotolerans changed distinctly.Great difference between samples was showed according to beta diversity index,and the maximum value reached 0.375.Acidithiobacillus ferrooxidans accounted for the highest proportion throughout the bioleaching process,and that of sample in the presence of 5 g·L^(−) AWF reached 28.63%.The results should show reference to application of agricultural wastes and low grade copper sulfide ores.

Beneficiation of a low grade limestone sample

Pilot scale column flotation studies were conducted on a low grade siliceous limestone ore. Silica content was reduced to less than 13g in the concentrate so that it became satisfactory for use in the paper or rubber industries. The limestone sample was crystalline and constituted primarily of calcite that contained quartz, feldspar, pyroxene, and biotite as gangue minerals. Quartz is the major silicate gangue whereas feldspar, pyroxene, and biotite exist in minor to trace quantities. Traces of pyrite were also observed within the sample. A reverse flotation process was adopted where the silicate gangue minerals were floated using two different commercial cationic collectors： Chem-750 F or Floatamine-D. The studies clearly suggest it is possible to produce a limestone concentrate assaying around 96-97% CaCO3 containing less than 1 % Si02. The effect of feed flow rate, percent solids, froth depth, and wash water on the grade and recovery of the CaC03 concentrate is discussed.

Conceptual study of X-braced frames with different steel grades using cyclic half-scale tests

In this paper, an experimental and analytical study of two half-scale steel X-braced flames with equal nominal shear strength under cyclic loading is described. In these tests, all members except the braces are similar. The braces are made of various steel grades to monitor the effects of seismic excitation. Internal stiffeners are employed to limit the local buckling and increase the fracture life of the steel bracing. A heavy central core is introduced at the intersection of the braces to decrease their effective length. Recent seismic specifications are considered in the design of the X-braced frame members to verify their efficiency. The failure modes of the X-braced frames are also illustrated. It is observed that the energy dissipation capacity, ultimate load capacity and ductility of the system increase considerably by using lower grade steel and proposed detailing. Analytical modeling of the specimens using nonlinear finite element software supports the experimental findings.

Progression from low-grade dysplasia to malignancy in patients with Barrett's esophagus diagnosed by two or more pathologists

AIM To evaluate annual incidence of low grade dysplasia(LGD) progression to high grade dysplasia(HGD) and/or esophageal adenocarcinoma(EAC) when diagnosis was made by two or more expert pathologists.METHODS Studies evaluating the progression of LGD to HGD or EAC were included. The diagnosis of LGD must be made by consensus of two or more expert gastrointestinal pathologists. Articles were searched in Medline, Pubmed, and Embase. Pooled proportions were calculated using fixed and random effects model. Heterogeneity among studies was assessed using the I2 statistic. RESULTS Initial search identified 721 reference articles, of which 53 were selected and reviewed. Twelve studies(n = 971) that met the inclusion criteria were included in this analysis. Among the total original LGD diagnoses in the included studies, only 37.49% reached the consensus LGD diagnosis after review by two or more expert pathologists. Total follow up period was 1532 patient-years. In the pooled consensus LGD patients, the annual incidence rate(AIR) of progression to HGD and or EAC was 10.35%(95%CI: 7.56-13.13) and progression to EAC was 5.18%(95%CI: 3.43-6.92). Among the patients down staged from original LGD diagnosis to No-dysplasia Barrett's esophagus, the AIR of progression to HGD and EAC was 0.65%(95%CI: 0.49-0.80). Among the patients down staged to Indefinite for dysplasia, the AIR of progression to HGD and EAC was 1.42%(95%CI: 1.19-1.65). In patients with consensus HGD diagnosis, the AIR of progression to EAC was 28.63%(95%CI: 13.98-43.27). CONCLUSION When LGD is diagnosed by consensus agreement of two or more expert pathologists, its progression towards malignancy seems to be at least three times the current estimates, however it could be up to 20 times the current estimates. Biopsies of all Barrett's esophagus patients with LGD should be reviewed by two expert gastroenterology pathologists. Follow-up strict surveillance programs should be in place for these patients.

Low Grade Fibromyxoid Sarcomas and Multiple Myeloma in the Same Patient： One Case Report and Literature Review

IntroductionMultiple myeloma （MM） is a neoplastic plasma cell dyscrasia char-acterized by anemia; a monoclonal protein（M-protein） in the serum and/or urine; abnormal bone radiographs and bone pain;hypercal-cemia; and renal insuf.ciency or failure.According to the results of immunoelectrophoresis, patients are separated to Ig type （IgG, IgA, IgD, IgE and IgM）; light chain; nonsecretory.

Low-grade chondrosarcoma of the larynx: A case report

BACKGROUND Chondrosarcomas of the larynx are malignant tumours that most commonly originate from the hyaline cartilage.Chondrosarcoma of the larynx,the most common type of low-grade tumour,accounts for 1%of all laryngeal neoplasms.CASE SUMMARY We present the case of a 60-year-old female patient who developed progressive hoarseness and shortness of breath over a 2-mo period.The patient had undergone resection of a laryngeal tumour 14 years before the aforementioned symptoms occurred,and histopathological analysis indicated that it was a chondroma.During the assessment of the patient,a submucosal,oval-shaped tumour was detected that was predominantly located on the left side of the larynx and was approximately 6 cm in size.The decision to perform left partial vertical laryngectomy was made.A pathohistological diagnosis of low-grade chondrosarcoma was made.Considering the results of pathohistological analysis and the positive margins of the resection,a total laryngectomy was performed.During the 12-mo follow-up,no local relapse or regional or distant metastases was detected.CONCLUSION Chondrosarcoma of the larynx must be considered in the differential diagnosis of laryngeal submucosal tumours.It is crucial to carefully sample of tumour tissue,differentiate chondroma and chondrosarcoma,and consider the possibility of malignant changes from chondroma to chondrosarcoma.

Heap-Leaching of Low-Grade Uranium Ore at SOMAIR： From Laboratory Tests to Production of 700 Tonnes U Per Year

In 2006, SOMAIR decided to increase the uranium production by 50% using heap leaching for the treatment of low grade ores. These ores, which come from different lodes with various properties, have been studied in four steps： （ 1 ） Lab tests： to compare the ores （characterization, acid consumptions, recovery...）; （2） Column tests on an average sample： to define significant parameters for a feasibility study; （3） Column tests on specific samples： to optimize recovery for each ore and identify problems of percolation due to the clays; （4） Pilot tests in large boxes （stalls）： to validate process parameters. Uranium production by heap leaching started in July 2009.

Experimental Study to Improve the Agronomic Efficiency of Low Grade Fine Size Rock Phosphate

Soluble phosphate fertilizers have been preferably used in plant crop production. The cost of applying conventional water soluble phosphate fertilizer is high in developing countries since their manufacturing requires importing high grade rock phosphate （RP）. As a result, the use of indigenously available low-grade RP is gaining importance globally. In this study, experiments were carried out using clayey loamy alkaline soil to evaluate the agronomic efficiency of fine sized low grade RP with inorganic nitrogen fertilizers and it was further compared with that of soluble phosphate fertilizer （di-ammonium phosphate）, Cicer arietinum was the test crops subjected to treatments of absolute control, di-ammonium phosphate and low grade RP with varying concentrations of ammonium sulphate or ammonium nitrate. The experiments were conducted during 2012-2013 in the bid to study the growth rate and the biomass of the crop. Tests were also performed to determine the residual effects of the fertilizers on the crops. The results revealed that the combined use of low grade RP and ammonium sulphate or ammonium nitrate, at 16 kg N/ha, resulted in an agronomic efficiency, in terms of biomass of plants, comparable to that of di-ammonium phosphate and was found to be a more attractive management option for resource-poor farmers.

Increased Detection of Polymicrobial Infections by Sonication and Significance of Prosthesis Design and Fixation Technique in Cases of Low-Grade PJI, a Retrospective Study

Introduction: Low-grade PJI remains a diagnostic dilemma in the medical community. It is mainly caused by low-virulent bacteria that cause chronic infection. This is mainly due to the formation of biofilms on the implant surface. This biofilm formation poses a diagnostic challenge that causes difficulties in the microbiological diagnosis of the infection by conventional culture methods. Sonication culture of implants has proven to be useful for biofilm forming bacteria. Therefore, we examined the evaluation of low-grade PJI using sonication culture methods and searched for influencing factors. The methods: Between October 2016 and November 2019 we retrospectively examined adult patients with suggestive clinical and laboratory findings of low-grade PJI. The patient's medical history, demographic information, prosthesis type, laboratory findings and length of hospital stay were collected. The results of the microbiological culture were divided into the results of the conventional preoperative and intraoperative culture method and the results of the sonication. In addition, laboratory chemical diagnostics of the joint punctures and CRP determination were performed. Additionally, the influence of prosthesis design and fixation technique, with and without cement, was investigated. The Results: Fifty-two patients with a mean age of 70.5 years were included in this study. The female population was more frequently affected. The most frequently affected joints were hip and knee. A higher percentage of pathogen detection was found at sonication with 60% of positive cultures, compared to 52% of intraoperative and 40% of preoperative conventional positive culture findings. The majority of patients were monomicrobial infections, with Staphylococcus epidermidis being the most frequently detected etiologic pathogen. The sonication culture was best able to detect a polymicrobial infection in 14% of cases compared to 6% of intraoperative and 4% of preoperative conventional cultures. Patients with a polymicrobial infection showed higher CRP values (P = 0.0172) and longer hospitalization (P = 0.0017) than monomicrobial infected patients. The results of the intraoperative conventional culture showed the highest congruence with the results of the sonication culture (concordance of 79%) compared to the preoperative culture. An infectious histopathological classification confirmed the microbiological ultrasound findings in 69% of cases with an infectious category. Cemented fixation showed a trend towards less positive microbiological findings, and total hip arthroplasty showed the highest detection of bacteria by sonication culture compared to bicondylar surface knee replacement (P = 0.0072). Conclusion: The sonication culture proved to be an important microbiological diagnostic tool, especially for the detection of polymicrobial infections in cases of low-grade PJI. This method has an established place in the diagnosis of low-grade PJI. The prosthesis design and the cemented fixation technique seem to have an influence on the detection of bacteria.

Low Grade Appendiceal Mucinous Neoplasm Presenting as a Mucocoele of the Appendix

Low grade appendiceal mucinous neoplasm (LAMN) is a rare malignancy with incidence of 0.7% to 1.7% of all appendicectomies [1]. LAMN has the worst complication of mucin seeding into adjacent peritoneum leading to pseudomyxoma peritonei. LAMN lacks standardised treatment approach where only appendicectomy is preferred for resection of non metastatic disease. Case Presentation A 38 yr old female presented with right lower quadrant where CT Abdomen revealed Mucocele of Appendix. Patient underwent Laparoscopic Appendicectomy and Histopathological examination revealed Low grade appendiceal mucinous neoplasm. Patient is on regular follow up and is disease free. Conclusion low grade appendiceal mucinous neoplasm is usually an incidental finding where treatment depends on staging and histology of the tumour.