Length Measurement Techniques Research Articles

A novel fiber length measurement technique for discontinuous fiber‐reinforced composites: A comparative study with existing methods

The residual fiber length in a molded part is one of the most important microstructural properties of discontinuous fiber‐reinforced composites. While there have been several research studies characterizing the process‐induced fiber length reduction, the measurement procedures vary substantially, calling into question the comparability of reported results. This article introduces a newly developed measurement procedure that aims to provide accurate, repeatable, robust, and time efficient fiber length analyses. A comprehensive study of measurement techniques was performed comparing commercially available systems and the conventional approach of measuring the fiber length manually. The results emphasize the need for a standardized procedure to characterize the fiber length distribution and the risk of generating inadequate results through improper sample preparation. The developed measurement technique was tested and compared for an experimental study of fiber breakage in injection molding. For a simple plaque geometry, the residual fiber length along the flow path was obtained for a long glass fiber‐reinforced polypropylene at 30 and 40%wt for varying process conditions. The new measurement technique showed accurate and repeatable results. The results of the injection molding study showed that screw speed and back pressure are important factors that drive fiber breakage. An increase in back pressure from 13 to 50 bar and screw speed from 27 to 35 rpm reduces the weight‐average fiber length by 37.5%. POLYM. COMPOS., 39:4058–4070, 2018. © 2017 Society of Plastics Engineers

Measurement of penile size in healthy Nigerian newborns using conventional penile length measurement technique

Objectives We attempted to establish a standard penile length for male newborn Nigerians using the conventional penile length measurement technique. Summary Defining the normal penile size in the neonate is paramount to making accurate diagnosis of abnormalities of the penis and the medical and surgical management of these anomalies. Patients and methods We carried out a prospective cross-sectional study of all term male neonates within 72 h of birth from April 2013 to March 2014 in the three largest obstetric centres (University College Hospital, Adeoyo Maternity Hospital and Our Lady of Apostles Catholic Hospital) in Ibadan, Nigeria. They underwent clinical examination, and their penile sizes were measured using the conventional penile length measurement technique. Results A total of 675 male Nigerian newborns were studied. The mean penile length was 3.14 ±0.65 cm, and the mean penile width was 0.97± 0.15 cm. Conclusion The penile dimensions obtained are comparable with reported values in previous studies in other parts of the world.

Elastic–plastic fracture toughness and rising JR-curve behavior of cortical bone is partially protected from irradiation–sterilization-induced degradation by ribose protectant

ObjectiveThis study tested the hypothesis that pre-treating cortical bone with ribose would protect the rising fracture resistance curve behavior and crack initiation fracture toughness of both bovine and human cortical bone from the degrading effects of γ-irradiation sterilization. Materials and methodsA ribose pre-treatment (1.8 M for bovine, and 1.2 M for human, in PBS at 60 °C for 24 h) was applied to single-edge notched bending fracture specimens prior to sterilization with a 33 kGy dose of γ-irradiation. Fracture resistance curves were generated with a single specimen method using an optical crack length measurement technique. The effect of the treatment on overall fracture resistance behavior, crack initiation fracture toughness, and tearing modulus was compared with non-irradiated and conventionally irradiation sterilized controls. Hydrothermal isometric tension testing was used to examine collagen network connectivity and thermal stability to explore relationships between collagen network quality and fracture resistance. ResultsThe ribose pre-treatment successfully protected the crack growth initiation fracture toughness of bovine and human bone by 32% and 63%, respectively. The rising JR-curve behavior was also partially protected. Furthermore, collagen connectivity and thermal stability followed similar patterns to those displayed by fracture toughness. ConclusionsThis paper demonstrates that the fracture toughness of irradiation-sterilized bone tissue can be partially protected with a ribose pre-treatment. This new approach shows potential for the production and clinical application of sterilized allografts with improved mechanical performance and durability.

Simulation of FEL pulse length calculation with THz streaking method.

Having accurate and comprehensive photon diagnostics for the X-ray pulses delivered by free-electron laser (FEL) facilities is of utmost importance. Along with various parameters of the photon beam (such as photon energy, beam intensity, etc.), the pulse length measurements are particularly useful both for the machine operators to measure the beam parameters and monitor the stability of the machine performance, and for the users carrying out pump-probe experiments at such facilities to better understand their measurement results. One of the most promising pulse length measurement techniques used for photon diagnostics is the THz streak camera which is capable of simultaneously measuring the lengths of the photon pulses and their arrival times with respect to the pump laser. This work presents simulations of a THz streak camera performance. The simulation procedure utilizes FEL pulses with two different photon energies in hard and soft X-ray regions, respectively. It recreates the energy spectra of the photoelectrons produced by the photon pulses and streaks them by a single-cycle THz pulse. Following the pulse-retrieval procedure of the THz streak camera, the lengths were calculated from the streaked spectra. To validate the pulse length calculation procedure, the precision and the accuracy of the method were estimated for streaking configuration corresponding to previously performed experiments. The obtained results show that for the discussed setup the method is capable of measuring FEL pulses with about a femtosecond accuracy and precision.

A comparison of cervical length measurement techniques for the prediction of spontaneous preterm birth

Objective: To evaluate the clinical utility of a novel means of assessing the cervix by measuring the angle of the curvature and to evaluate the performance of this technique as well as two other commonly used techniques of cervical length assessment in predicting spontaneous preterm birth (SPTB).Methods: This was a retrospective cohort analysis of singleton gestations with a history of SPTB. Transvaginal ultrasound images of cervical length obtained between 20 and 23 6/7 weeks were re-measured using three techniques: (1) straight linear distance between the internal and external os, (2) sum of two contiguous linear segments tracing the internal to the external os, and (3) measurement of the angle of the curve within the cervix using an electronic protractor. A short cervical length was defined as ≤25 mm.Results: A total of 181 women were included. The relative risk (RR) for SPTB by cervical angle ≤160° was 1.2 (95% CI 0.7–2.0) and the ROC curve revealed an area under the curve of 0.54 (95% CI 0.44–0.63). The RR for SPTB by short cervical length measured by the straight technique was 2.3 (95% CI 1.3–4.0) and by the segmental technique 2.1 (95% CI 1.2–3.8). There was a 99.4% agreement between the two techniques with an intraclass Kappa coefficient of 0.96.Conclusions: In women with a history of SPTB, cervical angle measurement does not correlate with the risk of SPTB. Cervical length measured via straight and segmental techniques had excellent agreement in identifying short cervix, and both identified a short cervix predictive of SPTB.

基于调制相移法的高准确度光纤长度测量技术

基于调制相移法的高准确度光纤长度测量技术

Patient satisfaction and penile morphology changes with postoperative penile rehabilitation 2 years after Coloplast Titan prosthesis.

A common complaint after inflatable penile prosthesis surgery is reduced penile length. We previously reported how using the Coloplast Titan inflatable penile prosthesis with aggressive new length measurement technique (NLMT) coupled with postoperative IPP rehabilitation of the implant for 1-year helped to improve patient satisfaction and erectile penile measurements. This is a 2 years follow-up of a prospective, three-center, study of 40 patients who underwent Titan prosthesis placement, with new length measurement technique for erectile dysfunction. Patient instructions were to inflate daily for 6 months and then inflate maximally for 1–2 h daily for 6–24 months. Fifteen penile measurements were taken before and immediately after surgery and at follow-up visits. Measurement changes were improved at 24 months as compared to immediately postoperative and at 12 months. 67.8% of subjects were satisfied with their length at 2 years, and 77% had perceived penile length that was longer (30.8%) or the same (46.2%) as prior to the surgery. 64.3% and 17.9% of subjects had increased and unchanged satisfaction, respectively, with penile length as compared to prior to penile implant surgery. All but one subject (96.5%) was satisfied with the overall function of his implant. This study suggests using the Coloplast Titan with aggressive cylinder sizing, and a postoperative penile rehabilitation inflation protocol can optimize patient satisfaction and erectile penile measurements at 2 years postimplant.

How to measure distal locking screws for intramedullary nails without a depth gauge.

Measuring length of distal locking screws is sometimes challenging owing to the gauge hook tethering soft tissues or failing to engage with the distal cortex. ‘Hand–eye’ memory is also lost when exchanging the drill for the depth gauge. This method measures the screw length accurately prior to setting up for the lateral view. Screws can be opened pre-emptively and inserted immediately after drilling. The majority of intramedullary nails are 10mm ±1.5mm in diameter. The known diameter of the nail (x) acts as a numerator (on an anteroposterior view) for the diameter of the bone (y). Using the fluoroscopic image and a ruler, measure the number of nail diameters that would be required to span the diameter of the bone. Figure 1 Annotated diagram of the distal locking screw length measurement technique

A novel technique for infant length measurement based on stereoscopic vision

BackgroundMonitoring infant growth is essential for evaluation of development and is an important indicator of health and illness. Length is an essential indicator of infant growth, however, length measurement methods...

Subpicosecond beam length measurement study based on theTM010mode

This article discusses a beam length measurement technique based on the ${\mathrm{TM}}_{010}$ modes of two cavities in frequency domain. Since the ${\mathrm{TM}}_{010}$ pickup monitor has a much better signal-to-noise ratio (SNR) than the other monitors, it can improve the measuring range and resolution limit of the beam length measurement in the frequency domain to achieve the real-time measurement of the pulse duration of the order of 1 ps or less with the resolution of about 10 fs. The root-mean-square length of a beam---which does not necessarily have a Gaussian distribution---can be obtained by choosing the working frequency of the cavity to be much less than the critical frequency of the beam. The modeling and analysis of the above theory were also made simultaneously. The resulting resolution was about 100 fs when the step size was chosen to be 200 fs in this simulation after the higher order mode coupling effect was eliminated and the beam offset was corrected by using the Bessel function. An efficient algorithm was also provided in case the measurement system would achieve the SNR of 112 dB when there could be some issue in signal processing. This algorithm can still provide the length result with the resolution of $3.5\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ for a beam duration of 0.1 ps when the SNR of the difference signal is as low as 10 dB.

Fatigue crack growth measurement in a superalloy at elevated temperature

Crack growth experiments at elevated temperature were performed in a nickel-based powder metallurgy (PM) superalloy. The crack propagation procedure was monitored by travelling microscope, high temperature extensometer and beachmarking technique. The appropriate creep crack growth relating parameter for the present alloy was discussed. The crack growth behaviours in standard compact tension specimens and side-grooved compact tension specimens were compared. Several crack length measurement techniques including beachmarking, linear correction and compliance measurement were discussed and the results were compared.

Re: Comparison of a New Length Measurement Technique for Inflatable Penile Prosthesis Implantation to Standard Techniques: Outcomes and Patient Satisfaction

Re: Comparison of a New Length Measurement Technique for Inflatable Penile Prosthesis Implantation to Standard Techniques: Outcomes and Patient Satisfaction

Inter-tester reliability of non-invasive technique for measurement of innominate motion

Although the complex anatomical orientation and position of the sacroiliac joints (SIJ) has rendered their 3D kinematic evaluation difficult, recent techniques of palpation–digitization of pelvic landmarks using electromagnetic tracking device have been able to accurately and non-invasively quantify the subtle SIJ kinematics. While this technique demonstrates radiographic validity and high test-retest reliability, it is yet to be assessed with regards to inter-tester and trial-to-trial reliability. A single-group repeated measure design using 4 testers was conducted to evaluate the inter-tester and trial-to-trial reliability of palpation–digitization technique for innominate vector length measurements using the Polhemus electromagnetic tracking device. Fourteen young, healthy adults between the ages of 18–40 years participated in the study. The innominate vector length was calculated from 3D co-ordinates of palpated and digitized pelvic landmarks in two test positions of hip. A sensitivity analysis was conducted to determine how palpation–digitization errors for pelvic landmarks impacts on innominate angle calculation. Reliability indexes of Intraclass correlation coefficient (ICC) (≥0.97) and Standard error of measurement (SEM) (≤2.02 mm) demonstrated very high inter-tester and trial-to-trial reliability and accuracy of palpation–digitization technique for innominate vector length measurements, irrespective of the two test positions. A higher consistency of measurements was obtained within-testers as compared to between testers, and sensitivity analysis demonstrated a negligible influence of palpation–digitization errors on the innominate angle measurements. The results support clinical and research utility of this technique for non-invasive kinematic evaluation of SIJ motion for this population. Further research on the use of this palpation–digitization technique in symptomatic population is warranted.

Axial length measurement techniques in pediatric eyes with cataract

Globe axial length (AL) in children is commonly measured using either contact or immersion technique. Office measurement of AL can be difficult in young children and infants and must often be done under anesthesia in an eye that is unable to cooperate with precise fixation and centration. Contact A-scan measurements yield shorter AL, on average, than immersion A-scan measurements in pediatric eyes. This difference is mainly the result of the anterior chamber depth rather than the lens thickness value. During intraocular lens power calculation, if globe axial length is measured by the contact technique, it will result in the use of an average 1-D stronger IOL power than is actually required. This can lead to induced myopia in the postoperative refraction. In our studied patients, there was a significant difference in prediction error between contact A-scan biometry and immersion A-scan biometry. The immersion A-scan technique is recommended for pediatric IOL power calculation. We also provide a review of biometry in pediatric eyes. The overall mean AL of pediatric cataractous eyes is significantly different than the mean AL of non cataractous eyes. More importantly, the standard deviation is higher in eyes with cataract than in those without. Three phases of eye growth in children have been documented: A rapid, postnatal phase from birth to 6months of age, followed by a slower, infantile phase from 6 to 18months of age, and finally a slow, juvenile phase from 18months forward. In our study, girls had shorter ALs than boys and African-American subjects had longer ALs than Caucasians. Eyes with unilateral cataract had shorter ALs than eyes with bilateral cataract during the earlier years, but had longer ALs during later childhood.

Comparison of a New Length Measurement Technique for Inflatable Penile Prosthesis Implantation to Standard Techniques: Outcomes and Patient Satisfaction

Within a study evaluating the redesigned AMS 700MS inflatable penile prosthesis (IPP) (American Medical Systems, Minnetonka, MN, USA), one site used new length measurement technique (NLMT), a more aggressive dilation and measurement of the corpora cavernosa on a stretched penis, to address penile shortening. To compare cylinder size and patient satisfaction, between a NLMT and traditional sizing for IPP implantation. Fourteen men received IPPs using NLMT, and 55 with traditional sizing. Nationwide sales data from 2005 to 2008 for AMS 700 IPPs was obtained from AMS for comparison; additional surveys captured patient satisfaction. Demographic data, cylinder sizes, and patient satisfaction were compared between the NLMT and standard techniques. The Fisher's exact test (P<0.001) showed a significant difference between the cylinder sizes with NLMT as compared with standard techniques. Of the 14 NLMT patients, 71.4% (10) received cylinders>21 cm long and 28.6% (4) received cylinders<21 cm long, as compared with 12.7% (7) and 87.3% (48), respectively, for patients implanted by traditional techniques. There were ethnic differences between the samples: 42.9% (6) NLMT patients were of African-American descent, as compared with 10.9% (6) in the standard technique group. However, longer cylinders were utilized more often, with 83.3% (5) of African-Americans treated using the NLMT; as compared with 33.3% (2) of the standard technique group. Nationwide data reveal 12.3% of patients routinely receive 21 cm cylinders. At 6 months postimplantation, patient satisfaction with NLMT was no different than standard techniques. There were no distal erosions, complications, infections, or pain concerns reported through 24 months among the NLMT patients. The NLMT resulted in a larger number of subjects implanted with larger cylinders. Satisfaction with performance and complication rates for NLMT patients was comparable to those implanted using standard techniques.

Impartial comparative analysis of measurement of leukocyte telomere length/DNA content by Southern blots and qPCR

Telomere length/DNA content has been measured in epidemiological/clinical settings with the goal of testing a host of hypotheses related to the biology of human aging, but often the conclusions of these studies have been inconsistent. These inconsistencies may stem from various reasons, including the use of different telomere length measurement techniques. Here, we report the first impartial evaluation of measurements of leukocyte telomere length by Southern blot of the terminal restriction fragments and quantitative PCR (qPCR) of telomere DNA content, expressed as the ratio of telomeric product (T)/single copy gene (S) product. Blind measurements on the same samples from 50 donors were performed in two independent laboratories on two different occasions. Both the qPCR and Southern blots displayed highly reproducible results as shown by r values > 0.9 for the correlations between results obtained by either method on two occasions. The inter-assay CV measurement for the qPCR was 6.45%, while that of the Southern blots was 1.74%. The relation between the results generated by Southern blots versus those generated by qPCR deviated from linearity. We discuss the ramifications of these findings with regard to measurements of telomere length/DNA content in epidemiological/clinical circumstances.

In Situ Leg Length Measurement Technique in Hip Arthroplasty

In situ femoral preparation refers to implanting a femoral component before the femoral neck osteotomy and without dislocating the hip joint, which allows the implanted femoral component to be used to measure leg length and offset. One hundred hip arthroplasty surgeries among 93 patients were compared with a control group of 15 patients. A modular neck femoral component was implanted in a technique similar to implanting a femoral nail. The differences between the in situ measurements and the preoperative and postoperative radiograph measurements averaged −0.1 mm for leg length ( r = 0.89) and −0.37 mm for offset ( r = 0.57). In situ leg length measurement allows accurate measurement of leg length and offset and guides surgeons in selecting appropriate modular components to attain a near anatomical hip arthroplasty.

Second Metatarsophalangeal Joint Instability and Second Metatarsal Length Association Depends on the Method of Measurement

Second metatarsophalangeal joint (MTPJ) instability is an important cause of forefoot pain and its causation multi-factorial. There is debate over an association with a relatively increased second metatarsal length and numerous measurement techniques. It is not known which, if any correlate with second MTPJ instability or their accuracy. We hypothesized that the method of measurement would affect the apparent relationship between second metatarsal length and second MTP instability. We analyzed standardized radiographs of 81 feet with second MTPJ instability using methods described by Coughlin, Maestro, and Hardy/Clapham. A control group of 11 feet were assessed from patients with a clinical diagnosis of Morton's neuroma (no instability) and successfully treated with a single steroid injection. The hallux valgus angle was also recorded. Patients mean age was 56 (range, 25 to 84) years, with female to male ratio of 4:1 and equal laterality. Second metatarsal length measurements were not significantly different between grades of instability using any method, although Kruskal-Wallis analysis revealed a significant association between instability grades and increasing age (p<0.05). Analysis of relative metatarsal lengths and second MTPJ instability revealed Coughlins method approached statistical significance (p < 0.055), but upon standardizing for age it became statistically significantly associated (r = 0.21, n83: p < 0.05). Spearman's rho correlation identified increasing hallux valgus was associated with decreased the second metatarsal length for Maestro and Hardy & Clapham methods (r = -0.29, n92: p < 0.005) and (r = -0.36, n86: p < 0.001), respectively. A positive correlation of second metatarsal length to second MTPJ instability existed using Coughlins method controlling for age. Maestro and Hardy & Clapham methods were possibly influenced by co-existing hallux valgus. The association of a clinical finding with a possible causative factor is likely influenced by its method of radiographic measurement.

Application of Newton’s method to determine the focal length of lenses using a lateral shearing interferometer and cyclic path optical configuration setup

We present a technique for the focal length measurement of lenses applying Newton's method, using a cyclic path optical configuration (CPOC) and a wedge shear plate (WSP). Two point sources of orthogonal linearly polarized light waves that have a known longitudinal separation between them are generated using CPOC. Selecting a particular state of polarization (s or p), the corresponding point source is made to coincide with the back focal point of the test lens (TL). The collimation of the output beam from TL is tested using the WSP. With a change in the state of polarization, a spherical wavefront would emerge from TL because the corresponding point source is situated slightly away from the focal plane of TL. The radius of curvature of the emerging spherical wavefront from TL approximated as image distance is evaluated by analyzing the shear fringes produced by WSP. Appropriate formulae for the determination of the focal length of TL, from the image distance and known longitudinal separation between the sources, are derived using Newton's method. Results obtained for a positive doublet lens of nominal focal length of 500.0 mm is presented.

Passive harmonically mode-locked fiber ring laser with long single-mode fiber and its application for high-resolution measurement of fiber length

Passive harmonically mode-locked fiber ring laser with long single-mode fiber SMF has been demonstrated. With the increase of nonlinearity due to the incorporation of a long SMF, it is found that the laser can operate in harmonic mode-locking states with various repeti- tion rates. Furthermore, based on the passively mode-locked fiber ring laser, a novel and simple technique for fiber length measurement with resolution on the order of centimeters has been proposed. The fiber length can be easily obtained from the fundamental cavity frequency of the mode-locked fiber laser because the transit time in a laser cavity is exactly proportional to the cavity length. © 2009 Society of Photo-Optical Instru-