Horizontal Screw Research Articles

The Incidence of Depressed Skull Fractures Due to the Use of Pin-Type Head Frame Systems in the Adult Population: 10-year Experience of a Single Neurosurgical Center

Pin-type head frame systems have become a worldwide standard procedure, but they can cause some complications on rare occasions. This study aimed to examine the incidence and associated risk factors of depressed skull fracture and related intracranial hematoma (DSFH) due to the use of head frames in our institute over the past 10 years. This study included 1749 patients who underwent neurosurgical surgeries using pin-type head frames, including the Mayfield (Integra NeuroSciences, Plainsboro, NJ) skull clamp (721 cases) and the Sugita (Mizuho Ikakogyo Co., Ltd., Tokyo, Japan) head frame (1028cases). We retrospectively reviewed hospital records of our institute to identify cases of DSFH, and documented the type of head frame used, as well as patient characteristics. The incidence of DSFH was 0.29% (5 of 1749 cases). All 5 cases had an associated epidural hematoma, with a single case having an additional dural laceration (without subdural damage). All perforation sites, located at the parietal bone near the pterion, occurred by the unilateral horizontal screw of the Sugita head frame. None of the patients experienced postoperative neurological decline. Even in the adult population, the DSFH by the pin-type head frame can occur infrequently. Based on our results, we recommend that the following factors should be considered when the pin-type head frame isused for neurosurgical procedures: location of pin application, thickness and fragility of the skull, and adequate control of compressive forces exerted by the head frame.

“Design and Development of Tractor Drawn Subsurface Manure and Seed Applicator”

Organic farming is now recognized as the best known alternative to the conventional agriculture, where cultivation and raising of crops and best quality of food is grown without any harm to the soil health, environmental and to the human being and microorganism present in the soil. Efficient organic nutrient supply to plant in adequate quantities to sustain most plant growth and yield while minimizing the environmental affected by the use of large quantities of inorganic fertilizers and pesticides which reduces the soil characteristics and productivity. Vermicom post is the major alternatives for organic farming with higher plant nutrients. Therefore, a tractor drawn subsurface manure and seed applicator was designed and developed in Farm Machinery and Power Engineering Department, G.B.P.U.A& T Pantnagar, Uttara khand for placement of vermicom post (organic manure) at a depth of 50 to 200 mm below the soil surface. Firstly the frame for vermicom post and seed hopper was fabricated according to the desired capacity of vermicom post manure hopper. Six rectangular orifices were provided for delivery of manure at the middle of the bottom surface of the manure hopper. A counter shaft was fixed on the frame which was driven by the ground wheel and rotated the horizontal screw conveyor shaft of the manure hopper as well as seed hopper shaft by means of chain - sprocket arrangement. The velocity ratios between the ground wheel and the manure and fluted roller shaft were 2:1. The manure hopper shaft and fluted roller shaft were rotated at 14, 35 and 41 rpm when tractor forward speed 2, 4 and 6 km/h, respectively. Two depth control side wheels were provided below the frame to adjust the depth of cut of machine in field operation. A furrow opener was designed to penetrate into the soil at the desired depth and placed the vermicom post and seed below the soil surface.

DEM investigation on conveying of non-spherical particles in a screw conveyor

Screw conveyors are extensively used in modern industry such as metallurgy, architecture and pharmaceutical due to their high-efficiency in the transportation of granular materials. And substantial efforts have been devoted to the study of the screw conveyors. Numerical method is an effective way to study screw conveyor. However, previous studies have mainly focused in the regime of spherical particles while the in-depth investigations for non-spherical particles that should be the most encountered in practical applications are still limited. In view of the above situations, discrete element method (DEM), which has been widely accepted in simulating the discrete systems, is utilized to investigate the conveying process of non-spherical particles in a horizontal screw conveyor, with particles being modeled by super-ellipsoids. In addition, a wear model called SIEM (Shear Impact Energy Model) is incorporated into DEM to predict the wear of screw conveyor. The DEM simulation results demonstrate that the particle shape is influential for the flow behaviors of particles and the wear of conveyor. The conveying performance evaluated quantitatively of both mass flow rate and power consumption is subsequently obtained to investigate the effect of sphericity of particle with different operation parameters. Moreover, particle collision frequency and collision energy consumption are acquired to investigate the possible particle breakage between particles and screw blade. The comparisons between particle–particle collision and particle–wall collision reveal that particles with large shape index have more possibility to be damaged in particle–wall impingement.

Continuous manufacture of hydroxychloroquine sulfate drug products via hot melt extrusion technology to meet increased demand during a global pandemic: From bench to pilot scale

During pandemics and global crises, drug shortages become critical as a result of increased demand, shortages in personnel and lockdown restrictions that disrupt the supply chain. The pharmaceutical industry is therefore moving towards continuous manufacturing instead of conventional batch manufacturing involving numerous steps, that normally occur at different sites. In order to validate the use of large-scale industrial processes, feasibility studies need to be performed using small-scale laboratory equipment. To that end, the scale-up of a continuous process and its effect on the critical quality attributes (CQAs) of the end product were investigated in this work. Hydroxychloroquine Sulphate (HCQS) was used as the model drug, Soluplus® as a model polymeric carrier and both horizontal and vertical twin screw extruders used to undertake this hot melt extrusion (HME) study. Seven formulations were processed using a small-scale horizontal extruder and a pilot-scale vertical extruder at various drug loadings, temperature profiles and screw speeds. When utilising a horizontal extruder, formulations with the highest drug load and processed at the lowest screw speed and temperature had the highest crystallinity with higher drug release rates. Upon scale-up to a vertical extruder, the crystallinity of the HCQS was significantly reduced, with less variation in both crystallinity and release profile across the different extrudates. This study demonstrates improved robustness with the pilot-scale vertical extruder compared to lab-scale horizontal extruder. The reduced variation with the vertical extruder will allow for short increases in production rate, with minimum impact on the CQAs of the final product enabling high-performance continuous manufacturing with minimum waste of raw materials. Finally, this research provides valuable information for the pharmaceutical industry in accessing continuous technologies for the manufacture of pharmaceutical products, allowing for efficient utilisation of resources upon scale-up and mass production during global pandemics and drug shortages.

Anatomic relationship between S2 sacroiliac screws' entry points and pelvic external branches of superior gluteal artery.

To study the relationship between the pelvic external branches of the superior gluteal artery and the entry area of the S2 sacroiliac screw to provide the anatomical basis and technical reference for avoiding the superior gluteal artery injury during the clinical screw placement. CTA imaging of superior gluteal artery of 74 healthy adults (37 males and 37 females) was randomly selected. The safe bony entry area ('safe area' for abbreviation) of S2 sacroiliac screw in the standard lateral view of the pelvis three-dimensional reconstruction CT image was determined by the CT auxiliary measurement software. The relationship between the pelvic external branches of the superior gluteal artery and the safe area of S2 sacroiliac screw was observed, and the cases in which the artery intersected the safe area were counted. The distance between the safe area and the superior gluteal artery branches closest to it was measured for the cases in which the artery and the safe area did not intersect. 21 of the 74 cases did not have a bone channel of horizontal S2 sacroiliac screw, so they were excluded from this study. In the remaining 53 cases, 12 cases had the deep superior branch of the superior gluteal artery through the safe area of S2 screw (22.6%), and 16 cases had the superficial branch of the superior gluteal artery through the safe area of S2 screw (30.2%). There was no obvious overlap feature and law between the safe area and the superficial and deep superior branches. In 20 cases of the 53 cases, the safe area of S2 screw was located between the deep superior branch and the superficial branch of superior gluteal artery (37.7%), and in 5 cases, the safe area of S2 screw was located behind the superficial branch of superior gluteal artery (9.4%). In the cases where the superior gluteal artery did not intersect the screw entry bony safe area, the part of superior gluteal artery closest to the safe area was located in front or back of the widest part of the safe area. The risk of accidental injury of the deep superior branch and superficial branch of the superior gluteal artery is high during the process of S2 sacroiliac screw placement. Even if the screw entry point is located in the bony safe area, the absolute safety of screw placement cannot be guaranteed. We strongly suggest that a careful and thorough plan is needed before surgery.

Investigation of a horizontal cone-shaped screw press for dehydrating sugar beet pulp

Investigation of a horizontal cone-shaped screw press for dehydrating sugar beet pulp

Comparative study of 3D printed navigation template-assisted atlantoaxial pedicle screws versus free-hand screws for type II odontoid fractures

The objective of the study was to compare the safety, efficacy, and accuracy of the pedicle screws with the three-dimensional (3D) printed navigation template to the free-hand screws for type II odontoid fractures. A total of 60 patients with type II odontoid fractures, treated with either template guiding pedicle screws or free-hand screws, were retrospectively assessed. The guiding group was treated with pedicle screws with the assistance of a virtual reality (VR) software-designed, 3D printed navigation template with two guide tubes. The safety rate and treatment efficacy of the screw placement, as well as the trajectory accuracy, were evaluated by respective measures and compared between two surgical groups. There were reduced surgical time (P < 0.05), blood loss (P < 0.01), and C-arm shots (P < 0.01) with 3D printed template guiding screws. The rates of safe pedicle screws in both C1 and C2 were significantly higher in 3D guiding group (P < 0.01) compared to the free-hand group, and the scores of visual analogue scale (VAS) and impairment scale (ASIA) were improved in guiding group at 1week post-surgery (P < 0.01 and P < 0.05, respectively). Postoperative CT and image reconstruction showed the 3D guiding group had better horizontal screw accuracy on both sides of C1 (L: P < 0.001, R: P < 0.01) and C2 (L: P < 0.001, R: P < 0.01) than free-hand group. The herein screw technique using 3D printed navigation template leads to greater improvement in the screw safety, efficacy, and accuracy, which may be a promising alternative to free-hand surgery for the treatment of odontoid fractures.

Technical exploration of horizontal screw centrifuge in solid-liquid separation of flowback liquid in offshore production

This paper introduces the structure and working principle of horizontal screw centrifuge with large length diameter ratio and its technological process in the separation of liquid-solid liquid in the flowback of offshore production. The effects of different water addition ratio, rotating speed and demulsifier content on the separation effect of centrifuge were investigated by indoor experiments. The orthogonal test was used to optimize the parameters, and the optimal combination of parameters was as follows: water ratio was 1.5/1, rotating speed was 3000r / min, demulsification was achieved The dosage was 400mg / L. The optimum rotating speed of the centrifuge is 2000r / min, and the field pilot test is carried out for 10 consecutive days with the best combination of parameters. The results are as follows: the average mechanical impurity rate of oil phase produced by horizontal screw centrifuge is 0.465%, and the average oil content in water phase is 183mg / L. The separation effect is stable.

The impact of particle size of cellulosic residue and solid loadings on enzymatic hydrolysis with a mass balance

Rice straw has a great potential for ethanol production due to its richness in polysaccharides and abundant availability, however, for efficient utilization of these polysaccharides, size reduction is a prerequisite step. Therefore, biomass particle size plays a vital role for cellulosic ethanol commercialization. In this study, the effects of rice straw particle size on dilute acid pretreatment efficiency and enzymatic hydrolysis are investigated. Different sizes; 5, 10 and 20 mm were subjected to dilute acid pretreatment in a continuous pilot scale system with a horizontal screw feeder reactor followed by enzymatic hydrolysis at varying solids (10 and 15%) and enzyme dosages (5 and 10 FPU/g of pretreated residue). The glucan hydrolysis for 5, 10 and 20 mm are 65.6, 80.0 and 60.0% using 5 FPU and 79.5, 93.4 and 72.8% using 10 FPU/g pretreated residue respectively at 10% loading, whereas, at 15% it is significantly lower in respective experiment. Overall sugar recovery with 10 mm is 63.8 and 72.9% with 5 and 10 FPU respectively. RS with 10 mm biomass particle size at both solid loadings and enzyme dosages resulted in much higher enzymatic hydrolysis than others and in turn the overall sugar recovery and this was found to be due to the variation in the degradation products and pseudolignin contents in the pretreated biomass. The insight into the structural intricacies of biomass after pretreatment are studied using FT-IR and SEM revealing significant changes in biomass properties responsible for improved sugar recovery.

Magneto-electro-elastic analysis of a strip containing multiple embedded and edge cracks under transient loading

This paper deals with the dynamic behavior of a magneto-electro-elastic strip weakened by multiple horizontal, vertical, and edge cracks within the framework of linear magneto-electro-elasticity. The analysis is based on stress and the magneto-electrical fields caused by horizontal and vertical Volterra-type screw dislocation in a medium. The problem was formulated through Fourier and Laplace transforms into singular integral equations in which the unknown variables are the jumps of displacement and magneto-electrical potential across the crack surface. The dislocation densities and the numerical Laplace inversion are then employed in order to derive the dynamic field intensity factors at the crack tips for both permeable and impermeable cracks. The effects of length and position of the cracks on the dynamic field intensity factors and interaction between the two cracks are investigated. Furthermore, the results show that, for a fixed value of mechanical load, the dynamic field intensity factor at the crack tips depends on the magnitude and direction of the applied magneto-electrical load.

METHOD OF CALCULATION OF PRODUCTIVITY AND POWER OF ROLL DEVICE WITH THE REGIME OF BACKUP

On the basis of the model of the process of movement and compaction of disperse mixtures in the roll gap after medium backup with a horizontal screw feeder the method of determination of integral characteristics of roller machine depending on the porosity of the working medium, its rheological properties and the structural and regime parameters of the designed device was proposed.

EVALUATION OF PRODUCTIVETY AND POWER OF SCREW FEEDER OF DISPERSE MEDIA

On the basis of performed mathematical modeling of process of movement and compaction of dispersed material in a horizontal screw the method was proposed of assessing productivity and power of the screw feeder of roller device taking into account the physical and mechanical characteristics deaerated environment and the apparatus parameters.

Discrete element model of particle transport and premixing action in modified screw conveyors

In this paper, five types of horizontal single-pitch screw conveyors with modified geometry, with three different lengths (400, 600 and 800 mm) were investigated for transport and auxiliary mixing action of two materials: natural zeolite and quartz aggregate (sand) with particle sizes 3, 4 and 5 mm. The geometry of the screw transporter is changed by welding three additional helices oriented in the same or the opposite direction from screw cutting edges, enabling the premixing of materials, during the transport. The proper mixing of the observed materials provides an adequate disposition of zeolite particles within the composite and prevents agglomeration and interference with cement hydration. Zeolite application as a binder in a building material is a possible solution to environmental pollution problems caused by cement production. The influences of screw length, particle diameter, the studied geometry variations of screw design, on the mixing performances of the screw conveyor-mixer during material transport were explored. All investigations were performed experimentally and numerically, by using Discrete Element Method (DEM). The experimental results and the results of the DEM investigation were used for the development of mathematical models for the prediction of mixing quality, which are presented in the form of second order polynomial and artificial neural network model.

Anatomical relation between S1 sacroiliac screws\u2019 entrance points and superior gluteal artery

BackgroundTo conduct radiologic anatomical study on the relation between S1 sacroiliac screws’ entry points and the route of the pelvic outer superior gluteal artery branches with the aim to provide the anatomical basis and technical reference for the avoidance of damage to the superior gluteal artery during the horizontal sacroiliac screw placement.MethodsSuperior gluteal artery CTA (CT angiography) vascular imaging of 74 healthy adults (37 women and 37 men) was done with 128-slice spiral CT (computed tomography). The CT attendant-measuring software was used to portray the “safe bony entrance area” (hereinafter referred to as “Safe Area”) of the S1 segment in the standard lateral pelvic view of three-dimensional reconstruction. The anatomical relation between S1 sacroiliac screws’ Safe Area and the pelvic outer superior gluteal artery branches was observed and recorded. The number of cases in which artery branches intersected the Safe Area was counted. The cases in which superior gluteal artery branches disjointed from the Safe Area were identified, and the shortest distance between the Safe Area and the superior gluteal artery branch closest to the Safe Area was measured.ResultsThree cases out of the 74 sample cases were excluded from this study as they were found to have no bony space for horizontal screw placement in S1 segment. Among the remaining 71 sample cases, there are 32 cases (45.1%) where the deep superior branch of superior gluteal artery passes through the Safe Area of S1 entrance point. There was no distinguishing feature and rule on how the deep superior branches and the Safe Area overlapped. In the 39 cases in which superior gluteal artery branches disjointed from the Safe Area, the deep superior branches of superior gluteal artery were the branches closest to the Safe Area and the part of the branch closest to the Safe Area was located in front of the widest part of the Safe Area. The shortest distance between the deep superior branch and the Safe Area is 0.86 ± 0.84 cm.ConclusionThere is a high risk of accidental injury of the deep superior branches of superior gluteal artery in the process of S1 sacroiliac screw placement. Even if the entry points are located in the safe bony entrance area, the absolute secure placement cannot be assured. We suggest that great attention should be paid to make thorough preoperative plans.

Minimally Invasive Cervical Pedicle Screw Fixation by a Posterolateral Approach for Acute Cervical Injury.

This is a retrospective case series. To avoid lateral misplacement of midcervical pedicle screws, T.T., one of our authors, developed a method for minimally invasive cervical pedicle screw (MICEPS) fixation by a posterolateral approach. We reviewed our initial experience with this fixation for trauma cases. Excellent clinical results with cervical screws have been reported for trauma cases. Although cervical pedicle screw fixation can be an essential part of reconstruction in spinal disorders, there is also a risk for injury to the vertebral artery. This study included 56 consecutive patients who received surgery for cervical fractures. We inserted a total of 203 cervical pedicle screws. Nineteen patients were treated by conventional methods. Thirty-seven patients were treated by MICEPS fixation. According to the MICEPS fixation, 12 patients were treated by unilateral fusion, 25 patients by bilateral fusion. All pedicle screws were inserted using spinal navigation system in the both groups. The average surgical time was 217 minutes with the conventional pedicle screw fixation and 165 minutes with the MICEPS fixation (P=0.0014). The average intraoperative bleeding was 560 mL in the conventional fixation and 140 mL in the MICEPS fixation (P<0.0001). Clinically significant screw deviation was significantly lower in the MICEPS fixation group than in the conventional cervical pedicle screw group (P=0.0039). There was not any deep wound infection in both groups. This intramuscular approach allows for horizontal pedicle screw insertion. This technique is probably useful for reducing intraoperative bleeding. In this study, incidence of screw perforation was significantly lower in the MICEPS fixation group than in the conventional cervical pedicle screw group. In particular, neither of the misplaced screws was laterally deviated in the MICEPS group.

Modeling residence-time distribution in horizontal screw hydrolysis reactors

The dilute-acid thermochemical hydrolysis step used in the production of liquid fuels from lignocellulosic biomass requires precise residence-time control to achieve high monomeric sugar yields. Difficulty has been encountered reproducing residence times and yields when small batch reaction conditions are scaled up to larger pilot-scale horizontal auger-tube type continuous reactors. A commonly used naive model estimated residence times of 6.2–16.7 min, but measured mean times were actually 1.4–2.2× the estimates. This study investigated how reactor residence-time distribution (RTD) is affected by reactor characteristics and operational conditions, and developed a method to accurately predict the RTD based on key parameters. Screw speed, reactor physical dimensions, throughput rate, and process material density were identified as major factors affecting both the mean and standard deviation of RTDs. The general shape of RTDs was consistent with a constant value determined for skewness. The Péclet number quantified reactor plug-flow performance, which ranged between 20 and 357.

Investigation of the treatment efficiency of fine-dispersed slime of a water rotation cycle of a metallurgical enterprise

The features of the water rotation cycle and the slime treatment system of the oxygen-converter shop of metallurgical production are investigated. During the audit, it is revealed that the concentration of suspended solids in the water cycle system varies in time up to 500 g/l for the condensed slime and up to 85 g/l in the pre-clarified water. It is established that the slimes of the metallurgical enterprise contain a finely dispersed solids fraction in the slime up to 93 % of a size of less than 20 μm and the residues of a cationic flocculant that impede effective treatment of the slime in the sedimentation tanks. This leads to the following drawbacks: a decrease in the slime treatment efficiency, removal of the fine fraction of solids together with clarified water of radial thickeners, regular replenishment of clean water, discharge of part of the flow into the slime collector. It is proposed to install an additional treatment module and use a more efficient anionic flocculant. It is recommended to monitor the efficiency of treatment and dosing of the flocculant depending on the solids concentration in the slime by continuous sampling and testing of slime flocculation. It is established that effective treatment up to 99 % can be achieved on the treatment module using anionic flocculant, thin-layer sedimentation tanks and sedimentation horizontal screw centrifuges.

Fixed Enclosure Guards and the Safety of Horizontal Screw Conveyors

One cannot overstate the value and ever growing importance of the screw conveyor and one cannot overemphasize the intrinsic danger associated with this classic monster. This danger can be controlled using fixed enclosure guards that are not only compatible with the function of screw conveyors but are anecdotally acknowledged to be the most desirable type of guard. Nevertheless, the speciality conveyor standards promulgate dangerous guarding systems with features two levels below the fixed barrier guard. This paper revisits the system of conveyor safety standards to rout out equivocal notions, expose shortcomings, and generally demonstrate that a foolish inconsistency is not the hobgoblin of small minds. Finally, this paper challenges the notion that a fixed enclosure guard is an elementary concept whose parameters are settled; e.g. a machine inside of a welded steel box. The definition of fixity and the duality of operation and maintenance are both explored.

Settling of virgin olive oil from horizontal screw solid bowl in static conditions.

This work was aimed to study the clarification efficiency of natural decantation in settling tank on virgin olive oil obtained from a two-ways continuous process. For this purpose, the impurities content of the virgin olive oil were monitored during settling process in settling tank at two different depths. Efficiency of purging system was determined for two days. The experiments were performed at industrial scale during three crop years. During the first minutes of settling was observed an ascent of the smaller organic particles of the oil. Then, most of the virgin olive oil impurities were settled at 300min, independently of the initial content of virgin olive oil. Finally, oil decantation showed slower rate. Higher clarification values were obtained for those decanter oils with higher impurities content, achieving clarification percentages between of 62.69 and 95.91% at 48h of settling. The highest settling efficiency was observed for those decanter oils with initial higher impurities content. The purging system used in the settling tanks was not able to remove the most of settled impurities since a considerable amount of the impurities remained in the tank after 48h, between 13.6 and 71.41% for the studied oils. In the tank purges was observed important oil losses. Therefore, decantation was not an efficient system for oil clarification since its settling capacity varied depending on the initial impurities content and due to the settled impurities can not be removed fully by purging system.

How clarification systems can affect virgin olive oil composition and quality at industrial scale

The effect of two different clarification systems, vertical centrifugal separator (VCS) with minimal water addition, and conical bottom settling tank (CBST), on virgin olive oil (VOO) composition and quality was studied at industrial scale for three crop years. In general, for the studied clarification systems, higher clarification values were reached for horizontal screw solid bowl (HSSB) oils with higher moisture and solid content. VCS showed higher clarification efficiency for HSSB oils with higher moisture and solid content. No notable differences were observed on the quality indices between evaluated clarification systems. Phenolic compounds showed a significant decrease when the HSSB oils were clarified by CBST. In general, a better sensory score was observed when the oils were clarified by VCS.Practical applications: The VCS with a minimal water addition could result a better option to produce VOO of improved quality, since is an efficient and quick operation that reduces the contact between oil and the remaining water and impurities content during the storage stage. This leads to prolong VOO shelf‐life and conservation of positive sensory notes, due to preservation of the quality indexes and minor components. Besides, this clarification system reduces the water consumption and generated wastewater regarding to conventional vertical centrifugation, and therefore can be considered more environmentally friendly.Effect of two different clarification systems (vertical centrifugal separator with minimal water addition and conical bottom settling tanks) on the virgin olive oil quality parameters, composition, and sensory characteristics.