Hard Stone Research Articles

EFFECTS OF CONTROLLABLE AND UNCONTROLLABLE PARAMETERS ON DIAMOND WIRE CUTTING PERFORMANCE USING STATISTICAL ANALYSIS: A CASE STUDY

Nowadays, most mining and quarrying industries utilize a diamond wire saw machine for bench cutting operations. This method uses a metal wire or cable assembled by diamond beads to cut the hard stone into large blocks. Many parameters classified into controllable and uncontrollable parameters affect the performance of the diamond wire saw cutting method. The uncontrollable parameters are related to rock engineering properties, and controllable parameters are related to operational aspects and machine performance. The diamond wire sawing process’s production rate is one of the most critical parameters influencing the design optimization and quarrying cost estimation. The cutting rate and wear rate of diamond beads are the most important factors to evaluate quarries’ production performance. This study aims to determine the effects of different controllable and uncontrollable parameters on different quarries’ production rates. Rock engineering properties like strength, hardness, and abrasivity, and operational aspects, such as cutting angle and drive wheel diameters, are considered as the main factors affecting the production performance of the diamond wire saw method. To discover the influence of these parameters, a detailed investigation in ten quarry operations was carried out. The relation between cutting rate and diamond bead wear with different parameters is estimated. It was observed that different controllable and uncontrollable parameters could increase or decrease the cutting rate and diamond bead wearing. Furthermore, using simple and multiple regression analysis, performance prediction of the cutting rate and wearing of diamond beads was developed, and the best equations were proposed.

The Effects of Chemical Disinfection on Dimensional Stability among Different Type of Impression Addition Silicon Materials

Introduction: Saliva and blood contaminated impressions are often a source of cross contamination between the clinic and dental laboratory. Explicit communication and observance of an infection control protocol for handling of dental impressions must exist among the office staff as well as between office and dental laboratories. Though disinfection of impression is routinely followed, autoclaving elastomeric impression is an effective method of sterilization them. Objectives: The purpose of this study was to evaluate dimensional stability and detail reproduction of a new addition silicon impression material after disinfection. Methods: In this study, a total of twenty impressions for the master model using heat resistant plastic stock trays. The twenty impressions were divided into two groups according to disinfection technique: (Table 2) Group 1: (n=10) Control group, untreated impressions. (C.G) Group 2: (n=10) Impressions were chemically disinfected. (D.G). after all impressions treatment, they were poured with extra hard stone (type IV) to get stone casts. Dimensional accuracy and detail reproduction of the impression material were evaluated indirectly through the recovered improved stone casts from impressions of the master model using the travelling microscope. Results: Cross arch distance (A): Epoxy resin master model cross arch distance measurement (A) was (41.36 mm). 1.1 Measurements of the cross-arch distance of stone casts Control group (C.G): The mean and standard deviation values of distance (A) in stone models obtained from C.G. were 41.553 ± 0.170 mm. Disinfection group (D.G): The mean and standard deviation values of distance (A) in stone models obtained from D.G were 41.368 ± 0.083 mm. ANOVA test showed that there was a statistically difference shrinkage between the groups (P-value = 0.006). 1.2 Measurement of the dimensional changes in the cross-arch distance of the different groups. The mean and standard deviation values of cross arch distance changes in stone models of C.G. were 0.191 ± 0.170 mm. while dimensional changes in stone models obtained from D.G. were 0.006 ± 0.082 mm. Conclusion: The purpose of this study was to evaluate dimensional stability and detail reproduction of a new addition silicon impression material after disinfection. In this study an epoxy resin master model was duplicated from a modified dentate mandibular model. Within the limitations of this study, it could be concluded that Chemical disinfectant of polyvinyl siloxane impression material can be successfully used in making fixed partial dentures.

New evidence for interregional interaction in the 3rd millennium BCE Aegean: Indus-style carnelian beads at Aegina-Kolonna, Greece

This study presents new evidence for long-distance cultural interactions in the mid-3rd millennium BCE as reflected by the hard stone beads from Aegina-Kolonna in Greece. There, nineteen carnelian beads and one of rock crystal were discovered in a small jewellery hoard. Our detailed restudy of these beads indicates that at least fifteen beads can be linked to the craft traditions of the Indus Valley civilisation. This is demonstrated through shared morphometric proportions, stylistic types, and scanning electron microscope investigation of drill hole impressions revealing the diagnostic use of Indus-style constricted cylindrical drills. While earlier scholars have already noted an Indus link for the single “etched” or bleached carnelian bead at the site, these new data provide additional evidence for more extensive long-distance interactions between the Aegean region, Mesopotamia and the Indus Valley in the 3rd millennium BCE.

The Feasibility of Pop-Dusting Using High-Power Laser (2 J × 50 Hz) in Retrograde Intrarenal Surgery for Renal Stones: Retrospective Single-Center Experience.

Objective: Recently, retrograde intrarenal surgery (RIRS) using laser lithotripsy has become popular. However, the optimal laser energy setting for pop-dusting has not been established. In this study, we report our experiences of RIRS using the high-power (up to 100 W) pop-dusting (HPPD) technique. Methods: This study retrospectively assessed 82 cases with RIRS using HPPD. Patients who underwent abdominal CT or mercaptoacetyltriglycine (MAG3) diuretic renal scan at 3 months postoperatively were included in this study. Patient and stone characteristics and perioperative and postoperative outcomes were evaluated. Results: The average number of renal stones was 3.67 ± 4.11, and the average length of the largest stones was 13.30 ± 6.41 mm. The mean Hounsfield units was 959.99 ± 384.73. The operation time was 58.10 ± 26.67 minutes. The mean HPPD time was 11.93 ± 9.48 minutes, with settings of 1.97 ± 0.25 J and 48.78 ± 3.29 Hz. The stone-free rate was 89%. The mean hospital stay was 1.68 ± 1.29 days. Pelvicaliceal and ureter injuries were observed in 9.8% and 32.9% of the study population, respectively. However, there was no transfusion, subcapsular hematoma, persistent urinary leakage, ureteral or infundibular stricture, or renal functional deterioration. There was transient postoperative fever in 12.2% of the study population. Conclusions: HPPD could be performed safely during RIRS for renal stones without significant complications such as collecting system injury or bleeding. High-power laser mode (up to 100 W) can be a safe and effective choice for pop-dusting during RIRS, especially for large and hard stones.

S1597 The Curious Case of a Missing Gallbladder: An Unusual Presentation of a Large Gallstone and Cholecystoduodenal Fistula

INTRODUCTION: Cholecystodudenal fistula is a rare complication of cholelithiasis. We present a unique endoscopically-treated case of a 5 cm gallstone that caused acute abdominal pain without gastric outlet obstruction in a middle-age female. CASE DESCRIPTION/METHODS: A 56-year-old woman with DM type II, hypertension, and BMI of 48 kg/m2 presented with acute right upper quadrant pain for 3 days. It was associated with nausea but no emesis, aggravating or alleviating factors. She had no prior abdominal surgeries. Vitals were normal. There was tenderness in the right upper quadrant but Murphy’s sign was negative. WBC, ALT, AST, total bilirubin and lipase were within normal limits. An ultrasound showed gallstones in a contracted gallbladder with no signs of cholecystitis. Robotic-assisted laparoscopic cholecystectomy was attempted, however, there was substantial amount of adhesions. Lysis of the adhesions was performed, then the duodenum and the stomach were found adhered to the gallbladder fossa. Thus, cholecystectomy was not deemed safe and the surgery was aborted. MRCP showed a minimal fluid collection in the gallbladder fossa but no evidence of bile duct stones or dilation. The gallbladder could not be identified. HIDA scan did not show it either. A CT scan of the abdomen revealed a cholecystoduodenal fistula along with air in a non-dilated biliary tree. EGD revealed a 5 cm golden-brown and hard stone and an inflamed and scarred fistulous opening in the bulb. The stone was too large to be retrieved through the pylorus. To prevent GI obstruction and to avoid a high-risk laparotomy, a large snare with a hard wire was used to break it down by forcefully pulling it against the plastic tip of the snare. The fragments were brought to the stomach for further fragmentation. The fragments were retrieved using stone baskets. Following the procedure, the symptoms improved. DISCUSSION: What was initially thought to be a classic case of symptomatic cholelithiasis was found to be a clinically, surgically, and endoscopically challenging cholecystoduodenal fistula. The fistula was not seen during an attempted cholecystectomy, nor was it seen on MRCP. Only CT then endoscopy revealed it. Large gallstones causing fistulas are very rare in the young. Laser, extracorporeal shockwave, and intracorporeal electrohydraulic lithotripsies have been used to treat large gallstones. Due to our limited resources, we performed mechanical fragmentation using the readily available stiff snares and stone baskets; a rarely reported approach.Figure 1.: Coronal oral and intravenous enhanced CT image of the abdomen demonstrates a large calculus (yellow arrow) with a few foci of air, as well as air within the biliary system (green arrow) suggesting choleduodenal fistula. A small amount of ascites surrounds the liver. There is also subcutaneous air within the right abdominal wall and adjacent to the gluteal muscles due to recent laparoscopy.Figure 2.: Endoscopic view of a large golden-brown, smooth and hard gallstone in the duodenal bulb. Erosion is seen on the wall of the duodenum.Figure 3.: Fragmentation of the large gallstone using a large-opening hard wire snare.

The Influence of Problem Gambling on Suicidal Ideation through Depression among Stayers in the Area of Casino: The Moderated Mediation Effect of Gender

This study has conducted to develop new gabion wall systems with vegetation base materials for stream bank stability and rapid rehabilitation. Vegetation base materials are primarily compounded with fine soil, organic composts and peat moss as plant fibers, a water retainer and a soil improver. Normally gabion wall systems resist the lateral earth pressures or stream power by their own weight. Therefore, fill material must have suitable weight, compressive strength and durability to resist the loading, as well as the effects of water and weathering. In this project, 100 to 200-mm clean, hard stones are basically specified, and about 50-mm rubbles are also used. Test application of new gabion wall system carried out in the stream bank of a small stream in the Gwangreung experimental forest, belonging to Korea Forest Research Institute (KFRI) in December 16th, 2006. As a result of the analysis of hydraulic stability of new gabion wall system, gabion wall system has highest threshold shear stress when the gabion wall covered by vegetation. New gabion wall system is highly resistant to sliding and overturning because safety coefficients exceed 1.5. As a result of term of slope stability analysis of new gabion wall system by Bishop and Fellenius methods, stability of stream bank was highly increased after the construction of gabion wall. Therefore, new gabion wall system is effective to stabilize unstable stream bank.

Stone clearance times with mini-percutaneous nephrolithotomy: Comparison of a 1.5 mm ballistic/ultrasonic mini-probe vs. laser.

A limitation of mini-percutaneous nephrolithotomy (mPCNL) is the narrow working channel of mini-nephroscopes, typically restricting instrumentation to 5 French (F) or smaller. We evaluated the efficacy of the 1.5 mm Swiss LithoClast ® Trilogy (Trilogy) rigid probe and compared the results to consecutive cases performed with a 30 W Holmium:YAG (Ho:YAG) laser. A retrospective review of 30 consecutive mPCNL cases using the Trilogy and 30 W Holmium laser was performed. A 12 F MIPS nephroscope with a 16.5 F access sheath and 6.7 F working channel was used for all mPCNL cases. The Trilogy was used with a disposable 1.5 mm × 440 mm probe with dual ultrasonic and ballistic energy. The Ho:YAG laser was used with a 550 micron fibre and a maximum of 30 W. Stone clearance time (SCT) was defined by the total time interval between activation of the lithotripter until insertion of the nephrostomy tube and measured in mm2/minutes. SCT included time for fragment retrieval, equipment adjustments, and rigid and flexible nephroscopy during and after lithotripsy. Eleven cases using a 1.5 mm Trilogy probe and 16 cases using a Ho:YAG laser met final inclusion criteria. Three cases using the Trilogy were excluded from final analysis due to conversion to alternative energy sources - two of those were upsized to standard PCNL and one was converted to laser. Mean stone diameter and density in the final Trilogy cohort was 26.7 mm and 1193 Hounsfield units (HU). Mean diameter and density in the laser cohort was 25.2 mm and 1049 HU. The mean stone area clearance time for Trilogy was 4.7±1.8 mm2/minute vs. 3.4±0.7 mm2/minute with Ho:YAG laser (p=0.21). For hard stones, defined as density >1000 HU, the Trilogy averaged 3.7±1.6 mm2/minutes, while the laser averaged 3.1±1.3 mm2/minutes (p=0.786). For soft stones, defined as <1000 HU, the Trilogy averaged 8.9±1.0 mm2/minutes compared to the Ho:YAG, which averaged 3.6±1.8mm2/minutes (p=0.019). No device-related complications occurred in either cohort. The 1.5 mm mPCNL Trilogy probe was comparable to 30 W Ho:YAG laser for clearing hard stones. The Trilogy performed better than laser on soft stones with a HU density <1000 HU.

Provinces inscriptions of Ancient Egyptian Votive Cubits نقوش الأقالیم على الذراع (وحدة قیاس الأطوال) النذرى المصرى القدیم

The votive cubits are those kinds of antiquities that have never been satisfactorily published, and called ceremonial cubit because of their high degree of decoration. The cubit mH is one of the first recorded units of length used by the ancient people. For the Ancient Egyptians it was the standard measure. Those kinds of votive cubits were not actually used as tools, but as votive, or were made for the funerary equipment and therefore more made of hard stone. The main goal of this paper is to explain some of their extraordinarily inscriptions. The searcher made a sort of a comparison between some votive cubits dating back to several periods, and studying the hieroglyphs text found on them. The present research aims to study the provinces of both Upper and Lower Egypt that decorated these kinds of the linear measure, and also their relation with the numerals which carved on. The searcher also makes a comparison with some other tables that appeared on other monuments that might pertain these kinds of inscriptions. الذراع النذري هو ذلک النوع من الآثار التي لم يتم دراستها أبدا بصورة مرضية، حيث يذخر هذا النوع من أدوات قياس الطول فى مصر القديمة بالعديد من النقوش المعقدة التى يصعب فهمها ودراستها. کلمة ذراع mH تستخدم أيضا کمدلول لأحدى وحدات قياس الطول حيث يعتبر المصريين القدماء من أقدم الشعوب أستخداما لهذه الوحدة. ولم يکن هذا النوع من الأذرع النذرية والتى فى الغالب مصنوعة من أحجار ثقيلة يستخدم فعليا کأداة قياس فى الحياة اليومية, ولکن کجزء من الأثاث الجنائزى أو للأحتفاظ بها فى المعبد. تهدف هذه الدراسة إلى المساعدة فى فهم وشرح تلک النقوش المثيرة للأهتمام, وللوصول لذلک أجريت نوعا من المقارنة بين بعض من تلک الأذرع النذرية التي يعود تاريخها إلى عدة فترات متفاوتة على مر التاريخ المصرى القديم، ودراسة النصوص التى نقشت عليها, من أجل تحقيق الهدف الرئيسى من هذا البحث الا وهو دراسة النقوش الخاصة بأقاليم مصر العليا والسفلى التى مثلت على أداة القياس تلک, وأيضا دراسة العلاقة بينها وبين الکثير من الأرقام المرتبطة بتلک الأقاليم. کما قام الباحث فى هذه الدراسة بإجراء مقارنة بين تلک النقوش التى تمثل الأقاليم على الأذرع النذرية وغيرها من الأثار الأخرى.

Indicators of Household Pottery Production: A Case-Study from the Chupicuaro Formative Culture

ABSTRACT Despite their reputation, little work has been carried out on Chupícuaro ceramics, and the organization of pottery production and its role in the economy of these populations are still poorly known. The excavations of the Chupícuaro project did not identify any pottery production areas, but uncovered fired clay coils and plaques and hard stone artifacts in the site of Cuizillo de Don Fidel Salinas (TR. 6). The techno-morphological study of these artifacts and the use-wear analysis of a sample show that they were specialized potters’ tools, designed to be adapted to the technical requirements of the composite shapes and used at specific stages of the chaîne opératoire. Moreover, contextual data show that pottery making was carried out in a domestic setting. This article places the tools at the core of the debate and shows that they can be an essential marker for identifying areas of ceramic production in Mesoamerica.

Bouveret’s syndrome: A challenging case of gastric outlet obstruction.

Bouveret’s syndrome causes gastric outlet obstruction when a gallstone is impacted in the duodenum or stomach via a bilioenteric fistula. We present case of a 40-year-old female presented with epigastric pain and intractable vomiting for 2 days. Her physical examination and laboratory workup including blood analysis, amylase test and lipase test were normal. Plain abdominal X-ray did not show any signs of small bowel obstruction. A nasogastric tube was placed and drained 2.5 L of gastric contents immediately. Esophagogastroduodenoscopy showed a dilated stomach with excessive secretions and a large blackish-brown hard stone in the duodenal bulb. After failed attempt at endoscopic extraction, patient underwent laparotomy and removal of stone via duodenal incision. Subsequently, the patient exhibited a good postoperative recovery. The condition of the patient has remained stable after being followed up for one year.

Retroperitoneal versus Transperitoneal Laparoscopic approach for Management of Upper Ureteric Stones

Abstract Background Current options for ureteral stones include medical treatment, extracorporeal shockwave lithotripsy (SWL), and various endoscopic procedures, with the standard open ureterolithotomy being less frequently practiced nowadays. The use of laparoscopy in the management of ureteral stones was one of the earliest applications of laparoscopy in urology, the first report being made by Wickham in 1979. Objective To compare the laparoscopic Retroperitoneal ureterolithotomy with the Laparoscopic Transperitoneal ureterolithotomy as a better alternative to conventional open surgery to extract a large, impacted and hard stones at the proximal two thirds of the ureter. Methods In this study we present our experience with laparoscopic ureterolithotomy comparing both transperitoneal approach and retroperitoneal approach through a retrospective randomized comparative study that conducted on 50 patients admitted through the outpatient clinic of Urology in Ain shams University Hospitals and Nasser institute hospital. The 50 patients divided into two groups each one was 25 patients, first group was performed by the laparoscopic transperitoneal approach and the other group by the laparoscopic retroperitoneal approach Between October 2017 and October 2018. Results This study revealed that the length of the Hospitalization period and the duration of drainage and urethral catheter were shorter in the transperitoneal approach than in the retroperitoneal approach with statistical significance between the groups. In the present study, the mean time to oral intake was significantly shorter in the Retroperitoneal group than in the Transperitoneal group. This is due to the mobilization of the colon, dissection and retraction of the viscera, and blood and urine leak in the peritoneal cavity, causing intestinal movements and sounds to be more delayed in the LTU group. In contrast, the lost blood during the retroperitoneal procedure does not come into contact with the bowel, and if urine leakage occurs, it would be contained within the retroperitoneal space. Also we find that both approaches are safe with few complications that were significantly wider at the transperitoneal group; vascular injury didn’t occur at any of the cases with no need for blood transfusion. Conclusion Through our study we concluded that Laparoscopic ureterolithotomy is technically feasible and safe and both of its two approaches either transperitoneal or retroperitoneal are successful procedures with a success rate nearly the same in both techniques, but and based on our results through this study, we recommend the retroperitoneal approach for laparoscpic extraction of the ureteral stones due to the fact that it has the least operative time than the transperitoneal approach, getting rid of the all stone burden, lower rate of complications and a better postoperative recovery.

Prospective Randomized Study of Fixed Laser Setting Verses Variable Laser Settings for a Better Stone Free Rate

OBJECTIVE: To assess the outcome of variable laser settings verses fixed setting on the stone free rate and complications. MATERIAL AND METHOD: We conducted a prospective, single-blind randomized controlled study. Solitary renal non lower pole stones 10 to 20 cm were included. A total of 113 Patients were randomly divided in to two groups. In group A, fixed laser setting was used at 1.0J energy and 12Hz frequency during the entire procedure. In Group B, variable laser settings were used; initial fine fragmentation was performed @ 1.0J X 12Hz. Once the residual stone reduced enough to wobble, the energy was reduced to 0.8 J and 8Hz. Settings were further reduced to 0.5J and 5Hz as required to complete the fragmentation process with minimal migration. RESULT: Group A had 58 patients and Group B 55 patients for analysis of perioperative variables. Stone free rate (<2mm) is in favor of systematic stone dusting with variable frequency (95.8% vs 83.6%, p=0.05). Post-operative fever and pain were not statistically significant between the groups (fever 10.3% vs 9.1%, p=1.00) (pain mean VAS 1/10 in group A vs 2/10 in group B). CONCLUSION: The solitary hard stones of 10 to 20 mm can be treated with more than 95% SFR using variable laser settings producing fine dust, without increase in significant postoperative complications or hospital stay.

Behaviour of hard stones submitted to different foot traffic

Building stones when submitted to wear conditions can change their appearance and eventually lose the characteristics for which they were chosen, leading to expensive and undesired material replacement. The physical–mechanical properties of the stones should fit their application purposes to ensure the desired durability, as in covering floors submitted to intense foot traffic. This paper presents the results of the evaluation carried out of some properties of the stone floor, composed of honed finished slabs of granite (Branco Micaela) and gabbronorite (Nero Impala), applied in a commercial zone for 10 years. The assessment of colour, roughness and gloss were carried out in 105 slabs. Beyond the colour differences, granite is lighter than gabbronorite, though both stones have chromatic homogeneity. There are also differences in surface roughness and gloss, with Branco Micaela showing a higher roughness and a lower gloss. Mineralogical composition, mainly the presence of micas, and the grain size govern the polishing of the stones, which affect the roughness and gloss. Nero Impala has large minerals and shows better polishing, whilst Branco Micaela, with more contacts and detachable micas, is more susceptible to losing mineral fragments, consequently showing higher roughness and less gloss. There is a wear difference between the areas of high and low pedestrian foot traffic, though these differences do not significantly modify the aesthetic characteristics of the floor. The use of honed finishing proved to be a good option to prevent the undesirable evolution of surface characteristics.

Comparison of wear characteristics of diamond segments under different sawing modes in sawing hard stone

In this study, the wear characteristics of two kinds of diamond segments with different composition of matrix were compared and investigated under two sawing modes through an experiment. Diamond particles were studied through scanning electron microscopy and three dimensional imaging system. Then, the remaining height of diamond segments was measured by digital vernier caliper. The wear characteristics of diamond segments were analyzed from wear morphology, protrusion height of diamond particles and the remaining height of diamond segments. The motion of two sawing modes and their effects on trajectories were analyzed which presented that the rocking reciprocating sawing mode can reduce sawing length and sawing time compared with horizontal reciprocating sawing mode used daily in industry. The results of experiment demonstrated that the main wear mechanism attributed to diamond segments wear is the fracture and falling of diamond particles caused by heavy loads especially in rocking reciprocating sawing mode. The average protrusion height of diamond particles is related with loads and the bonding strength of matrix. However, diamond segments wear can be effectively reduced in rocking reciprocating sawing mode while cobalt-based segments were adopted because a higher bonding strength to diamond particles can be provided compared with iron-based segments. The matrix of segments can be abrased slower while sawing length and sawing time were reduced.

Vaporizing Effect of the Popcorn Technique for Laser Lithotripsy: Comparing the Different Settings of High Energy in a Caliceal Model.

Objective: To assess the effectiveness of laser lithotripsy in different holmium:yttrium aluminum garnet (Ho-YAG) laser settings with a wide range of energies, frequencies, and power. Materials and Methods: Two types of phantom stones were utilized, including soft stone, which mimics uric acid stone, and hard stone, which mimics calcium oxalate monohydrate stone. The stones were made into a round shape measuring 10 mm in diameter. The lithotripsy settings were 1 J × 20 Hz, 2 J × 10 Hz, 1.5 J × 20 Hz, 3 J × 10 Hz, and 2 J × 20 Hz. The lithotripsy was conducted in a caliceal model with a 2-mm filter. All stone vanishing from the artificial calix was an end point of the experiment. All fragments that passed through the filter of each setting were dried and weighed to calculate the vaporizing effect as well as to compare among the different settings. Laser fiber degradation was compared by using these settings. Results: Disintegration efficiency was determined by time consumption and the amount of vaporized stone. The best time consumption was 8 min 51 sec for 2 J × 20 Hz for hard stone and 5 min 13 sec for this setting for soft stone. The most vaporizing effect for hard stone was 92.19% for 2 J × 20 Hz and 87.30% for this setting for soft stone. The most fiber tip degradation was 28 mm for 3 J × 10 Hz for hard stone and 4 mm for 1.5 J × 20 Hz for soft stone. Conclusion: The study revealed that the best setting for hard stone was 2 J × 20 Hz, which was the fastest for achieving maximum vaporization, whereas fiber degeneration was comparable to others. For soft stone, there was no difference among the settings.

An effective FDTD model for GPR to detect the material of hard objects buried in tillage soil layer

It is difficult to systematically classify and detect objects buried in tillage soil layers. There is no effective way to detect destructive objects in the soil. This paper presents a method and model of intelligently classifying hard objects of electromagnetic wave based on Finite Difference Time Domain (FDTD), especially the volume and shape of the object can destroy agricultural machinery in farming. It aims to improve the environmental detection technology of agricultural machinery and break through the limit of intelligent equipment. Firstly, in order to calculate the energy amplitude loss function of plane electromagnetic waves in farmland soil layer, the optimal Soil Layer and Electromagnetic Wave Model (SEM) is determined by using Blackman-Harris pulse as the excitation source; The absorption boundary condition of Uniaxial Perfectly Matched Layer (UPML) is also determined by test. Secondly, the forward modeling is performed by REFLEX and MATLAB software programming, the grid type forward modeling results, compared to electromagnetic wave results and real-time forward measured data by GPR in layered soil, there were verification and analysis. Measuring the relationship between different phase amplitude and electromagnetic wave energy between different materials, proved by experiment, the optimized 750 MHz excitation source function was verified experimentally and accuracy rate reached to 0.98 or 0.99 with FDTD model. The precision of actual depth and calculated depth of the object are not more than 0.02 m. The multi-channel amplitude analysis of five kinds of material of electromagnetic waves of metal, wood, PVC plastic, dry hard stone, and glass is obtained by SEM in different soil layers, and the classification accuracy is 100%, the optimal value of energy discrimination peak amplitudes of these five materials are 0.0183, 0.0028, 0.0043, 0.0069 and 0.0087. The research shows that the FDTD difference method is used to simulate the propagation mechanism of electromagnetic waves in the soil. The SEM of GPR forward modeling can be established efficiently and accurately. The results can provide theoretical and technical support for the GPR soil matter or objects classification system and agricultural machine farming modules to detect objects buried in the soil layer.

Combining fuzzy RES with GA for predicting wear performance of circular diamond saw in hard rock cutting process

Predicting the wear performance of circular diamond saw in the process of sawing hard dimensional stone is an important step in reducing production costs in the stone sawing industry. In the present research work, the effective parameters on circular diamond saw wear are defined, and then the weight of each parameter is determined through adopting a fuzzy rock engineering system (Fuzzy RES) based on defining an accurate Gaussian pattern in fuzzy logic with analogous weighting. After this step, genetic algorithm (GA) is used to determine the levels of the four major variables and the amounts of the saw wear (output parameter) in the classification operation based on the fixed, dissimilar, and logarithmic spanning methods. Finally, a mathematical relationship is suggested for evaluation of the accuracy of the proposed models. The main contribution of our method is the novelty of combination of these methods in fuzzy RES. Before this work, all Fuzzy RESs only use simple membership functions and uniform spanning. Using GA for spanning and normal distribution as membership function based upon our latest work is the first work in fuzzy RES. To verify the selected proposed model, rock mechanics tests are conducted on nine hard stone samples, and the diamond saw wear is measured and compared with the proposed model. According to the results obtained, the proposed model exhibits acceptable capabilities in predicting the circular diamond saw wear.

Zur Datierung und Deutung der Chlamysfiguren aus rotem Porphyr

The article deals with four porphyry statues wearing late antique tunica-chlamys attire in Vienna, Berlin, Ravenna and in the Louvre. By the provenance of two of them and by deals of workmanship they are all clearly linked to the porphyry workshop that the tetrarchs had installed in Egypt. Yet they differ from the main products of this workshop not only by their new costume but also in their overall shape. Whereas the tetrarchs employed local sculptors, who specialized in working hard stone for their new porphyry workshop and the result was a fascinating mixture of imperially commissioned and strong local elements, these chlamydate follow other models of more classical taste. They attest to new imperial instructions given to the workshop. This makes it important to know when this new form of imperial representation was introduced. Suggested dates differ widely this article proposes to date the statues in Ravenna and the Louvre by means of their close typological and stylistic similarities to the statue of Oikoumenios form Aphrodisias, which itself is dated by its portrait, which is the closest known parallel to early Theodosian emperor’s portraits at Aphrodisias and Constantinople. The common link between the locally-produced honorific statues from Aphrodisias, the imperial porphyry workshop in Egypt, and the statue finds in Italy would then be Constantinople, whose sculpture workshops were heavily influenced by those of Aphrodisias. There are reasons to see the statues at Vienna and Berlin as earlier and representing a development o the new iconography. All this seems to correspond with the ideas of U. Gehn and R.R. R. Smith, who posit, that the use of late antique chlamydate and togati for honorific statues developed mainly in the later 4th century and in the east. It may have evolved during and after the reign of Valens, parallel to the intensified lawgiving concerning status marking. There should e parallels to this in the emperor’s ‘Chlamys/Dienstkostüm’. - In the end, there are some remarks on the ‘hand-on-sword’ gesture of the statues.

Investigation of the effect of boron carbide-doped diamond sockets on cutting performance in granite cutting

In the study, boron carbide was added to the matrix in different ratios in order to increase the wear resistance of the socket matrix and to strengthen the bond at the matrix interface with the diamond. Under the same sintering conditions, eight different tool sockets were produced. One of them is boron carbide non-doped (0% B4C) reference socket. The others are boron carbide-doped sockets in different ratios (1-2-3-4-5-6-7% B4C). The produced sockets were welded around a 350-mm saw to produce circular saws. In the study, firstly, the metallographic properties of the boron carbide non-doped (0% B4C) and boron carbide-doped (1-2-3-4-5-6-7% B4C) sockets such as theoretical densities, unit volume weights, porosity, Knoop hardness (HK), and weight wear loss were determined. Cutting experiments were then carried out (under constant cutting conditions) with eight different circular saws on a single hard stone species with a homogeneous structure. At the end of cutting experiments, the power consumption, specific cutting energy, specific abrasion, and noise levels of each saw were determined. Cutting performance of boron carbide non-doped and doped circular saws has been investigated taking into account the metallographic properties of the sockets. At the end of the study, the lowest power consumption and specific cutting energy consumption due to high porosity and low hardness were obtained at 7% B4C-doped sockets. It was determined that the lowest specific abrasion value was found in sockets with 4% B4C doped due to the low porosity and high hardness value, and the lowest noise level was found in 1% B4C-doped sockets.

Pratiques funéraires et dynamique spatiale à Oakaie 1, une nécropole à la transition du Néolithique à l’Âge du Bronze au Myanmar (Birmanie)

En Asie du Sud-Est, la fin de la préhistoire – de l’apparition de l’agriculture à la naissance de proto-États – ne dure que de 1500 à 2000 ans. Les cimetières sont des sites essentiels pour comprendre ces changements marqués par des influences culturelles indiennes et chinoises. Le Myanmar est le seul pays d’Asie du Sud-Est avec lequel ces pays partagent une frontière terrestre. Les données archéologiques nouvellement acquises pour le Myanmar permettent d’éclairer cette période charnière. Cet article présente les résultats de l’étude de la nécropole d’Oakaie 1 (région de Sagaing), fouillée durant deux saisons entre 2014 et 2015 dans le cadre de la Mission Archéologique Française au Myanmar (MAFM). La nécropole est datée entre la fin du Néolithique et le début de l’âge du Bronze. Les 55 sépultures et 57 inhumés mis au jour permettent d’analyser l’évolution des pratiques funéraires pendant plusieurs siècles. L’organisation de l’espace sépulcral est particulière. Les fosses, organisées en rangées sont distribuées selon deux grandes orientations, N-S et NNO-SSE. Les inhumations sont individuelles ou plurielles (9 cas) et, dans un cas, un chien a été inhumé avec des humains. L’analyse taphonomique suggère l’usage de contenants périssables larges ou étroits, avec des bords montants, probablement des troncs d’arbres évidés. Les biens funéraires les plus communs sont des céramiques généralement placées près des membres inférieurs ou dans le comblement de la fosse. Des éléments de parure (perles en coquillages et en pierre, bracelets en pierre polie et en matière dure animale) étaient aussi associés aux défunts, tandis qu’une unique sépulture a fourni un objet en métal (une hache en bronze). L’usage croisé de critères variés, dont l’organisation spatiale de la nécropole, les recoupements de sépultures, les pratiques funéraires et le mobilier déposé auprès des défunts a permis d’établir que la nécropole a fonctionné durant trois phases. La première est caractérisée par 20 inhumations orientées dans un axe N-S, généralement individuelles, dotées d’un mobilier funéraire réduit constitué d’une seule céramique et de rares éléments de parure en coquillage et matière dure animale. La deuxième phase est composée de 30 sépultures orientées dans un axe NNO-SSE. Elles contiennent des inhumations individuelles et plurielles associées à des céramiques distinctes de celles rencontrées lors de la première phase et à des objets de parures, dont certains sont d’origine exotique, plus nombreux et plus fréquents. La troisième phase est représentée par une inhumation, exceptionnellement riche pour la nécropole. Le défunt était associé à 19 céramiques, une perle en pierre et une hache en bronze. Ce dépôt présente un parallèle avec des sépultures de la nécropole de Nyaung’gan située à 2,7 km de Oakaie 1. Notre analyse permet d’établir que les deux premières phases correspondent à une utilisation intermittente de la nécropole par une même population alors que la troisième marque une rupture lié à l’introduction du métal.